Issue Unable to send Mail

[Gosmart]

Server operating system version

Ubuntu

Plesk version and microupdate number

Plesk Obsidian Web Admin Se Edition 18.0.54

I can receive the mail from Plesk Server, but I cannot send it to my personal email or other emails from Plesk Server.
and also I allowed the TCP Port 25 on the Plesk firewall.

 

[WebHostingAce]

Some hosting companies block the outgoing on Port 25. You can not unblock this via the Plesk Firewall. Only the hosting company can do this for you.

Please check "Tools & Setting > Mail Server Settings" and if it says the Port 25 is Blocked.

 

[Gosmart]

 

[Peter Debik]

It seems that too much spam - or what GMail thinks is spam - was sent to GMail from your ip address. They blocked your ip.