OKI MC332, MC362 and MC562 Cannot Send Scans by E-mail: SMTP Setup for Gmail and Microsoft 365

Last Updated on 07.08.2026 by DriverNew

If the OKI MC332, MC362 or MC562 scans a document but does not send it by e-mail, reinstalling the scanner driver on the computer is usually not required. When using the Scan to E-mail function, the MFP connects to the SMTP server by itself and sends the message with the file. The computer, TWAIN/WIA driver and ActKey utility are not involved in this operation.

To restore sending, you need to determine at which stage the error occurs: the MFP cannot find the mail server, cannot establish a secure connection, receives a sign-in rejection, or successfully transfers the message but the mail system then blocks it. Below is a complete setup procedure from scratch and separate solutions for the messages Please check SMTP settings, SMTP Login failed, SMTP Authentication unsupported and Please check DNS settings. The message text may differ slightly depending on the control panel language and firmware version.

Models This Guide Applies To

The setup procedure applies to the following MFPs:

• OKI MC332dn;
• OKI MC342dn and MC342dw;
• OKI MC352dn;
• OKI MC362dn and MC362w;
• OKI MC562dn, MC562w and MC562dw;
• OKI ES3452 MFP;
• OKI ES5462 MFP and ES5462dw MFP;
• OKI MPS2731mc.

The names of individual menu items may differ, but all of the listed models provide an SMTP server address, port, SMTPS and STARTTLS modes, sender address, authentication method, user name and password.

Identify the Cause by the Message or Symptom

What to Prepare Before Setup

Do not start by trying random ports and encryption methods. First prepare the following information:

• the MFP’s IP address on the local network;
• the MFP administrator password;
• the exact SMTP server name;
• the SMTP port;
• the encryption mode: SMTPS, STARTTLS or None;
• the authentication method: SMTP or None;
• the full user name, usually the same as the e-mail address;
• the account password or a separate app password;
• a sender address that the server allows you to use.

If the mail account belongs to an organization, obtain the settings from its administrator. You cannot determine the settings solely from the ending of the e-mail address: an organization may use its own SMTP relay even if its mailboxes are hosted in Google Workspace or Microsoft 365.

Step 1. Check the MFP Network Settings

SMTP will not work if the device is connected to the local network but does not have a gateway for Internet access or a DNS server for finding the mail server.

1. Find the MFP’s IP address on the control panel or in the printed network configuration report.
2. On a computer connected to the same network, open a browser.
3. Enter the device’s IP address, for example:

http://192.168.1.40

4. If the OKI web page opens, the computer can see the MFP on the local network. If it does not open, restore the device’s network connection first.
5. On the control panel, press the SETTING button.
6. Open Easy Setup > Network Setting.
7. Check the IP address, subnet mask, default gateway and DNS server.
8. If addresses are assigned automatically by the router, the router address usually serves as both the gateway and DNS server. Do not enter arbitrary values if you do not know the network settings.
9. Check the MFP’s date, time and time zone. A significantly incorrect time may interfere with certificate validation during a secure connection.

If the SMTP server is specified by name, for example smtp.gmail.com, working DNS is required. For Microsoft 365, you should also use the name smtp.office365.com, not an IP address found on the Internet: service addresses can change, and the certificate is issued for the server name.

Additional Check from a Computer

The following commands show whether the server is accessible from your network. They do not check the password stored in the MFP and do not prove that its TLS implementation is compatible with the server.

1. Press Win + R, enter powershell and press Enter.
2. To check DNS, run:

nslookup smtp.gmail.com

3. To check port 587, run:

Test-NetConnection smtp.gmail.com -Port 587

• If nslookup does not return an address, check DNS on the router and with your Internet service provider.
• If TcpTestSucceeded : False is shown, the port may be blocked by the router, the organization’s firewall or the Internet service provider.
• If both tests succeed, proceed to the SMTP settings on the MFP.

Step 2. Open the E-mail Settings

You can enter the settings from the control panel, but it is more convenient to enter a long address and password through the MFP’s built-in web page.

Configuration Through a Browser

1. Open http://MFP-IP-address in a browser.
2. Sign in as an administrator.
3. For the factory configuration of this series, the web interface administrator name is root and the password is aaaaaa. If the password was changed previously, use the configured password.
4. Open Admin Setup > Network > E-mail > Send Settings.
5. Open the detailed SMTP protocol settings.
6. Enter the server, port, encryption, authentication method, user name, password and sender address.
7. Click Submit and wait for the device’s network subsystem to restart.

Configuration from the Control Panel

1. Press the SETTING button.
2. Select Easy Setup and press OK.
3. Enter the administrator password and confirm it.
4. Open E-mail Setting.
5. Enter the SMTP server address.
6. Enter the device’s e-mail address in the sender field.
7. For the normal Scan to E-mail function, select Disable in the Receive Setting field. Receiving mail through POP3 is usually not required for sending scans.
8. If the server requires a user name and password, select SMTP in the Authentication Method field.
9. Enter the SMTP User ID and SMTP Password.
10. Save the settings.
11. Then open SETTING > Admin Setup > Network Menu > Mail Server Setup.
12. Check SMTP Port and SMTP Encryption.

Leave the POP3 Server, POP User ID and POP Password fields empty unless the mail administrator specifically provided POP before SMTP settings. This authentication method is outdated and is not required for Gmail or Microsoft 365.

Step 3. Do Not Mix Up the Port and Encryption

This table does not replace your provider’s settings. If the administrator specified a different port, use the combination they provided. Do not select None for a password-protected account over the Internet if the server supports a secure connection.

Step 4. Configure Sending Through Gmail

A regular Google Account password is often not accepted by an older MFP. For direct sending through Gmail, you usually need to enable 2-Step Verification and create a separate app password.

Create a Google App Password

1. Sign in to the Google Account that will be used only for sending scans.
2. Open Manage your Google Account > Security.
3. Enable 2-Step Verification if it is not already enabled.
4. Open the App passwords section.
5. Create a password with a clear name, for example OKI scanner.
6. Copy the generated 16-character password. This value is shown only once.
7. Enter it in the MFP’s SMTP Password field instead of the regular account password. If the password is displayed in groups separated by spaces, enter all 16 characters without the spaces.

If the App passwords section is unavailable, the reason may be a managed organization account, Advanced Protection or a 2-Step Verification policy. Do not disable account protection. Check the requirements on the Sign in with app passwords page. For Google Workspace, configure SMTP Relay instead or use another SMTP service approved by the administrator.

smtp.gmail.com Settings

Configure one option completely first. If port 465 with SMTPS does not work, change the port to 587 and the encryption to STARTTLS at the same time. Do not leave the port from the first option with the encryption from the second.

Google Workspace SMTP Relay

For an organization, a separate relay that accepts messages from an allowed external IP address is preferable. The administrator first configures the service in Google Admin and then enters the provided settings on the MFP.

• server: smtp-relay.gmail.com;
• available ports: 25, 465 or 587;
• encryption and authentication: according to the configured relay rule;
• sender address: an address or domain permitted by the rule.

Do not change Authentication Method to None until the administrator confirms that the relay identifies the organization by its static external IP address. Google’s step-by-step options for printers and scanners are provided on the Send email from a printer, scanner, or app page.

Step 5. Configure Sending Through Microsoft 365

Microsoft 365 supports several different methods. First determine whether the MFP will sign in to a dedicated mailbox or send messages through a corporate relay. These methods must not be combined.

Option 1. Client SMTP Submission Through smtp.office365.com

On the Microsoft 365 side, Authenticated SMTP must be enabled for the selected mailbox. The administrator can check it as follows:

1. Open Microsoft 365 admin center.
2. Go to Users > Active users.
3. Select the account used by the MFP.
4. Open the Mail tab.
5. Open Manage email apps.
6. Check the status of Authenticated SMTP.

If Security Defaults are enabled in the organization or SMTP AUTH is blocked by policy, enabling a single switch for the user may not help. Do not disable organization-wide protection for an older MFP. Switch to SMTP Relay or another approved sending method.

Option 2. Microsoft 365 SMTP Relay

This option requires a Microsoft 365 administrator and either a static external IP address for the organization or a suitable certificate. The general configuration is as follows:

1. The administrator determines the domain’s MX address, for example example-com.mail.protection.outlook.com.
2. In Exchange admin center, an inbound connector from the organization’s mail server to Microsoft 365 is created.
3. The connector specifies the static external IP address from which messages will be received.
4. The MFP is configured with the domain’s MX address and port 25.
5. Authentication Method is set to None if the connector identifies the sender by IP address.
6. In the From field, enter an address from the organization’s accepted domain.
7. The administrator checks SPF and the ability to send to internal and external recipients.

Port 25 must be allowed by the network’s outbound rules and by the Internet service provider. Do not expose the MFP to the Internet and do not create a publicly accessible SMTP relay. A detailed comparison of Client SMTP submission, SMTP Relay and Direct Send is provided in the Microsoft 365: Set up a multifunction device to send email guide.

Option 3. Direct Send to Internal Recipients Only

Direct Send connects to the organization’s MX address over port 25 without a user name and password. It is suitable if scans need to be delivered only to recipients inside Microsoft 365. Messages to external recipients are not relayed using this method.

If sending to employees within the organization works but sending to Gmail, Outlook.com or another external address does not, this may be a normal Direct Send limitation rather than an MFP malfunction.

Step 6. Perform a Minimal Test from the Control Panel

The first test should create a small file. This prevents an attachment size limit from hiding an SMTP error.

1. Place one page face up in the ADF or face down on the platen glass.
2. Press the SCAN button.
3. Select E-mail and press OK.
4. Open Add Destination > To > Direct Input.
5. Enter the recipient’s address and confirm it.
6. Open Scan Settings.
7. Select PDF as the format.
8. Set the resolution to 200 dpi or 300 dpi.
9. For the first test, use monochrome or grayscale scanning.
10. Press MONO. To test color sending after the first successful test, repeat the operation using COLOR.
11. Wait for the completion message or write down the exact error text.

After changing settings, test only one account and one recipient. Changing the server, port, password and sender address at the same time makes it difficult to identify the cause.

Please check SMTP settings Error

This message means that the MFP could not establish the required connection to the SMTP server. Perform the following checks in order:

1. Compare the server name with the mail provider’s documentation. Remove any spaces at the beginning or end of the field.
2. Check the default gateway and DNS in the MFP’s network settings.
3. Check the port and encryption combination: 465 with SMTPS or 587 with STARTTLS, if that is what the provider specifies.
4. If port 25 is used, find out whether the Internet service provider blocks it.
5. Temporarily create a minimal one-page test to rule out an oversized file.
6. Restart the MFP after saving the network settings and try sending again.

Do not substitute a Gmail or Microsoft 365 IP address for the server name. If the name cannot be resolved, fix DNS. Using a random IP address may cause another error after the service address changes or during certificate validation.

Please check DNS settings Error

1. Open SETTING > Easy Setup > Network Setting.
2. Check DNS Server (Primary).
3. If the network uses DHCP, compare the MFP’s DNS settings with those of a computer on the same network.
4. Check that the default gateway is on the same subnet as the MFP’s IP address.
5. Make sure the SMTP server name is entered without https://, a slash or a port number.

A correct SMTP Server field looks like smtp.gmail.com, not https://smtp.gmail.com:587/. The port is entered in a separate field.

SMTP Login failed Error

In this case, the server is accessible but has rejected the credentials or sender address.

1. Enter the full e-mail address in SMTP User ID, including the part after the @ symbol.
2. Delete the stored password and enter it again. Check letter case and accidental spaces.
3. For Gmail, use an app password rather than the regular account password.
4. For Microsoft 365, check whether Authenticated SMTP is enabled for the selected mailbox.
5. Enter the same address in the From field that is used for sign-in.
6. If the From address must be different, the Microsoft 365 administrator must grant the account Send As permission, while Google Workspace must allow that address through a sending rule.
7. Check whether the mailbox is blocked and whether its password was changed recently.

The error may appear after multifactor protection is enabled even if the regular password itself has not changed. This is a change in sign-in rules, not a scanner malfunction.

SMTP Authentication unsupported Error

This message usually means that the authentication method selected on the MFP does not match the server.

• For smtp.gmail.com and smtp.office365.com, select SMTP, not POP.
• For a relay that identifies the organization by its static IP address, None may be required.
• Do not select POP before SMTP unless the provider specifically supplied a POP3 server and confirmed the use of this outdated method.
• If the server accepts only OAuth and the MFP offers only a user name and password, a direct connection is incompatible. Use an SMTP relay.

The Message Was Sent but Is Not in the Inbox

1. Check the Spam and Junk Email folders.
2. If Microsoft 365 is used, ask the administrator to check quarantine and Message Trace.
3. If Google Workspace is used, check Email Log Search.
4. Compare the From address with the permitted sender.
5. Send a test first to an address within the same domain, then to an external address.
6. If an internal address receives the message but an external address does not, check Direct Send or restricted SMTP server limitations.
7. When sending through a relay, check SPF and other domain rules.

A successful transmission message on the control panel confirms only that the SMTP server accepted the message. The server may still place it in quarantine, reject it during further delivery or apply restrictions to external recipients.

A Small Scan Is Sent, but a Large File Is Not

1. Set the resolution to 200 or 300 dpi instead of 600 dpi.
2. For text documents, select monochrome mode or grayscale.
3. Use PDF and higher compression.
4. Split a large document into several messages.
5. Check the message size limit on both the sending and receiving servers.
6. If documents are regularly large, configure Scan to Shared Folder and send a link or an already reduced file by e-mail.

The size of the original pages is not the same as the size of the final e-mail: high-resolution color scanning creates a large file, and e-mail attachment encoding further increases the message size.

Sending Works Only Sometimes

Intermittent errors are more difficult to distinguish from incorrect settings. Check the following causes:

1. Make sure the MFP has a stable network connection. If possible, use Ethernet instead of weak Wi-Fi.
2. Check whether the gateway and DNS change after the router restarts.
3. Check the device’s date and time.
4. Repeat the test with one page to rule out size and transmission time limits.
5. Make sure the app password has not been revoked and the account is not being blocked by a security policy.
6. Check the mail system logs: the server may be limiting the sending rate or temporarily rejecting messages.
7. Compare the MFP firmware version with the version available for the exact model.

If the Correct Settings Do Not Help: Check TLS and Firmware

Microsoft 365 requires TLS 1.2 or later for Client SMTP submission. The manuals for this series list SMTPS and STARTTLS, but do not specify a particular TLS version for SMTP. Therefore, the presence of a STARTTLS option by itself does not guarantee compatibility with a modern server.

1. Write down the current firmware version from the device information.
2. Open the support page for your exact OKI model.
3. Compare the installed version with the available version.
4. If the firmware is outdated, update it with stable power and a stable network connection.
5. After the update, check the server, port, encryption and minimal test sending again.
6. If the server continues to reject the secure connection, do not disable TLS. Use a compatible SMTP relay between the MFP and the mail system.

If the Mail Server No Longer Supports the MFP’s Capabilities

If the server requires OAuth but the MFP supports only SMTP authentication with a user name and password, re-entering the credentials will not solve the problem. The following secure options are available:

• configure Google Workspace SMTP Relay;
• configure Microsoft 365 SMTP Relay using a connector and a static external IP address;
• use a secure local SMTP relay that accepts messages only from the MFP’s IP address and forwards them to a modern service;
• use a separate SMTP provider that supports older devices over a secure connection;
• save documents using Scan to Shared Folder and then send them from the computer.

The relay must not accept messages from arbitrary devices on the Internet. Restrict access by the MFP’s local IP address, firewall rules and permitted sender addresses.