SMTP error 550 Invalid HELO name

I created a domain, user, mailbox, trying to send mail, I get an error as in the screenshot

what am I doing wrong?

You can find the reason and a solution here:

Basicly: use a domain name, not the ip, for webmail (domain.tld/webmail) and it will work.

1 Like

Thank!!! This tip helped solve the problem:

But it’s better to leave it there and just use a domain name for access webmail instead.

Yes, but so far it’s convenient for me.
In the future, of course, so be it.