I can't send or receive emails

I already tried several solutions that I found in the forum but I couldn’t make progress, I also updated cyberpanel but nothing.
If I use an alias with the main domain, they bounce when sending and if I send from another account it says:
Action: delayed
Final-Recipient: rfc822;info@ergcloud.net
Status: 4.0.0
Remote-MTA: dns; mail.ergcloud.net

If I send from an alias of another domain hosted on the same server, it bounces, and when I send from another account to the alias in cyberpanel it says: Unrouteable address

With mailjet I was able to send, but I have to authorize the domains one by one and that’s not the idea.

I want to create the client’s website and by giving him his access data he can create aliases, send and receive emails using snappy or rainloop.

Cyberpanel is installed in a google cloud instance, and despite the fact that ports 465 and 587 are open when I use Email Debuger it shows me that both ports and 25 are closed.
Thank you in advance if someone can help me.

Those ports are closed from Google you need to request them to open those. But what I know they won’t open those easily… Better use third party mail service or other VPS provider.

Hello

I have the same problem despite the ports are open, e.g. 25:

root@cyberpanel:~# telnet 162.55.37.58 25
Trying 162.55.37.58...
Connected to 162.55.37.58.
Escape character is '^]'.
220 cyberpanel.borsedilussoartigianali.com ESMTP Postfix

and Postfix’s currently running:

root@cyberpanel:~# systemctl status postfix
postfix.service - Postfix Mail Transport Agent
     Loaded: loaded (/lib/systemd/system/postfix.service; disabled; vendor preset: enabled)
     Active: active (exited) since Fri 2023-01-20 21:18:47 UTC; 11min ago
       Docs: man:postfix(1)
    Process: 492837 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
   Main PID: 492837 (code=exited, status=0/SUCCESS)
        CPU: 1ms

Jan 20 21:18:47 cyberpanel.borsedilussoartigianali.com systemd[1]: Starting Postfix Mail Transport Agent...
Jan 20 21:18:47 cyberpanel.borsedilussoartigianali.com systemd[1]: Finished Postfix Mail Transport Agent.

Any kind suggestion?

Thank you in advance.

Test’s outcome towards an external e-mail (in this case GMail):

454 4.7.0 TLS not available due to local problem

Thank you for any assistance.