- Plesk for Linux
Unable to send email from Outlook or Thunderbird from a certain location:
CONFIG_TEXT: Send test email message: Outlook cannot connect to your outgoing (SMTP) email server. If you continue to receive this message, contact your server administrator or internet service provider (ISP).
From other locations Outlook and Thunderbird are working fine. Email is working fine from the webmail from all computers.
Port for inbound SMTP connections is blocked by the firewall (for example default port 25) on an Internet Service provider side on the specific network.
Allow connections to SMTP port that is used (by default it is port 25) on the firewall on the server where issue is reproduced. If no firewall is blocking the connection to 25 port, contact Internet Service provider.
Note: On a Google Cloud port 25 is blocked by default. See the following article for additional details:
How to send email from a Plesk server on Google Cloud?