Hostname/IP does not match certificate's altnames

I just try to send one email and I get:
Hostname/IP does not match certificate’s altnames: Host: is not in the cert’s altnames:,
The cyberpanel web email works though.
My mail server runs on postfix - on CyberPanel.
Hope someone can help!

your domain’s ssl is good.

if you talk about the mail …

as far as i can see

you only need change your computer’s dns
then flush the dns ipconfig /flushdns

but, if …

what mail client you use ?

Hmm…I’m using nodemailer, which is a way to send email via code. I also tried the default mail app on Windows just as a test, but it didn’t even let me log in - it says we couldn’t find info for that account.
The config I’m using with nodemailer is:
port: 25
TLS disabled

work fine at gmail