SMTP Settings Troubleshooting

While you might encounter the failure issue during testing and normal operations (send/receive the Email failed) with the Email account.

Before the troubleshooting, you would need to log in the SSH for executing commands. Refer here

Step 1. Ensure the device could access the Internet

Try to use ping & nslookup command to test smtp domain.

If failed, please check whether the DNS address is available or not.

Step 2. Check the SMTP/POP3 Servers’ Settings

The protocol by default

  • The SMTP Server’s port is 25 by default.
  • The POP3 Server’s port is 110 by default.

Enable the TLS protocol (For the Gmail or the Exchange Server)

  • The SMTP Server’s TLS port is 587.
  • The POP3 Server’s TLS port is 995.


For Gmail or Exchange server, you need to enable the TLS protocol.


Step 3. Enable the SMTP/POP/IMAP options of Email Servers

Gmail Server

Step 4. Run ssmtp debug and some typical reply error codes

S-Series PBX

Enter the SSH global interface, go to the corresponding folder and create one xxx.eml file.

And then, running the ssmtp debug command to see the debug details.

cd /ysdisk/support/tmp/

vi testsystemailbox.eml 

From: the administrator’s Email address of PBX

To: the destination’s Email address, would be the administrator’s by default. (User can change the destination email address in the line of “TO” filed)

ssmtp -D /ysdisk/etc/mailbox/sysmail -vt </ysdisk/support/tmp/testsysmailbox.eml 


For TGv3 Gateway

Use the following commands to test:

touch /ysdisk/support/mail.eml

ssmtpsms -vt < /ysdisk/support/tmp/mail.eml


For U-Series, TGv2 and other gateways

Refer this guide: SMTP Debug For MyPBX & Gateways


The Typical Errors

  • Locked Port

This may be caused by the router/firewall security policies has enabled the restriction to SMTP port 25.

  • Wrong Password (535 Error)

This error means this Email Server’s password should be the Authentication code.

  • Wrong Password (535 Error)

This error means Password Authentication is failed, check if the password is correct or includes the special characters or not.

  • Locked account (534 Error)

Send-mail: Authorization failed 534 5.7.14, this problem may be caused by the Gmail account has been locked out due to many 3rd party less secure apps tried to log in this mail account, use this link Unlock Gmail Account and click CONTINUE to unlock this account.


Have more questions? Submit a request


Please sign in to leave a comment.