POSTFIX : no relay, no external sending

[calport]

Hello @gpsau and welcome to the community.

@gpsau

No Relay, No sending to external sites. Local delivery is fine.

It might be your VPS provider blocking port 25. See

IMAP & SMTP - clients connected but no communications with other servers

Check first of all if your VPS provider has blocked port 25 and it is this which is preventing your system from sending out mail - and if so, see Use Virtualmin’s webmail on port 20000 to check if the incoming mail has landed in the mailbox.