Problem in Sending emails(undeliverable emails)

[sohailsoh]

Dear All,

I have developed an application with sending an email alert to users.

But i am having problem that email is returned back from some users with the following message

undeliverable to test@test.test

Body of message generated response:

500 5.5.0 Syntax error - line too long

Original message follows.

Please advise on this issue.

Thank you,

Regards

[ripken204]

give us all of the code that you are using for sending out the emails.