SMTP Outbound Group Emails show Error 500: Unkown Error

[Nth20]

I set up everything correctly in the Main tab and the IMAP connection test was successful but for the SMPT test, I got the Error 500: Unknown Error. Where can I check the logs and how to solve this error please?

[abnbcorp]

I actually got the same error, I have not received any solution for this issue. Not sure if there are support answers to this one. hopefully someone can answer.

[lazovic]

Hi Nth20,

To understand the cause of the problem, you need to enable debug mode for EspoCRM instance logs: https://docs.espocrm.com/administrat...ng/#debug-mode.

Then press on the "Test Connection" button for IMAP and the "Send Test Email" one for SMTP and check the logs. EspoCRM log files are located in the {ESPO_ROOT}/data/logs/ directory.

[Nth20]

Thanks Iazovic, I did and it showed the following log please:
[2025-07-28 04:17:37] ERROR: (535) Email sending error: Failed to authenticate on SMTP server with username "info@kingexp...(my email)" using the following authenticators: "LOGIN". Authenticator "LOGIN" returned "Expected response code "235" but got code "535", with message "535 Incorrect authentication data".". :: /home/beallcar/vietnamrail...(my website)/(my espocrm route)/vendor/symfony/mailer/Transport/Smtp/EsmtpTransport.php(226)
[2025-07-28 04:17:37] WARNING: Email sending:unknownError; 0

Can you help please?

[lazovic]

Nth20,

Please tell me, do you use a custom email provider or the Google or Outlook email provider?

[Nth20]

Nth20,

Please tell me, do you use a custom email provider or the Google or Outlook email provider?

Thanks Iazovic, I use custom email provider (Hosting.com (former A2 hosting) please. The host is mail.mywebsite.com please

[lazovic]

Nth20,

You should check if there are any restrictions for SMTP on the hosting itself in the admin panel. For example, you can check in Home > Security Center > SMTP Restrictions. It depends on the admin panel. Perhaps you should contact the technical support of the hosting itself.