Undelivered Mail Returned to Sender

#1

I’m a new user of mxroute. I need to send some emails to my customer but it seems that the IP of our server is locked by the other party. How can I solve this problem?
his is the mail system at host relay0213.mxlogin.com.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.
550 Mail content denied
  [NPOs41J75OyFHW/j0VygIURKlVVNIxfGspKjTSY/h1qqSuDvhJ+AoYY= IP:
   199.181.239.213].
#2

Hi!

I urge you to come to the Slack channel with this … there you will be able to have a real time discussion with @Jarland or @Louis who can assist with this.

#3

Hey friend,

In this case, it means that the recipient server has rejected the content of the email that you have sent.