Mails are not sent from Plesk server. Plesk server displays Port 25 is blocked message in dashboard. It was working/sending mails till recently.

What we have tried:

• Checked that Amazon(LightSail) dashboard has port 25 open.

• Windows firewall is added with an exception to allow port 25 on both inbound and outbound rules though Firewall is managed by Symantec.

• Exception added to Symantec Endpoint protection, to allow port 25.

• Plesk Firewall also has port 25 open.

After trying all these still the Plesk server dashboard displays port 25 is blocked warning.

Any other configurations that we missed to check, any other ideas.

Also Question2Answer emails were not working with SMTP servers on Plesk. Hence defaulted to using local email on port 25.

  • Something we used to use years ago before everyone locked it down was to Telnet to troubleshoot ports we were having troubles with. Not sure if it would still work if Telnet has been blocked.
    – Trebor
    Mar 16, 2020 at 14:15
  • Have you tried port 26?
    – Steve
    Mar 16, 2020 at 21:08

1 Answer 1


After trying many solutions, I found out that my hosting provider was blocking SMTP ports. This caused my connection to time out while sending emails.

Call your hosting provider, perhaps they are blocking SMTP ports in your case too.


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