SMTP e-mail error with Non-English journals

Hi all,
I have set up the SMTP configuration of our OJS and everything words fine with English journals, I mean all emails deliver successfully. Unfortunately, emails of Non-English journals (Persian/Farsi) do not deliver at all. The error on the SMTP server side is as follow:
said: 554 5.6.0 Reject BAD HEADER (in reply to end of DATA command)
I think the problem is with the characters and maybe the encoding. Any suggestions would be appreciated.

Can you get the SMTP headers associated with this SMTP error message? Provide them to your SMTP administrator, or post them here for review.

I would also check on your character encoding settings in vs. the character data in your database.