Mail rejected: "550 Maximum line length exceeded" error?

[MatthewAiden]

Hello,

I have the following issue w/ my forum (2.0.17).

After the user is registered (immidiate registration), I'm getting the following email:
====
This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

[email protected]
host hxxp:5817.smtp.antispamcloud.com [nonactive] [130.117.54.107]
SMTP error from remote mail server after end of data:
550 Maximum line length exceeded (see RFC 5322 2.1.1).
====

How would you approach debugging this issue? I have no idea what email is being sent from the forum that violates 1000 character rule.

Thank You!

[Dzonny]

Hey there and welcome to SMF community!

What forum language are you using?
Are you getting this upon every user registration, or this is an isolated case?
Are you using any additional mod for sending welcome messages upon user registration maybe?