Error 550

[Serafin96]

I don't know why does this message appear. Can somebody help me? It also appears another message in the same 550 error, but it said that is abuse on reply.

This is the mail system at host gateway20.websitewelcome.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.

                   The mail system

<*****@*****.com>: host mx1c9.megamailservers.com[69.156.240.34]
    said: 550 5.7.1 H:DYNB [192.185.44.20] Connection refused due to abuse.
    Please contact your E-mail provider. (in reply to MAIL FROM command)

[alec]

Your server landed on a blacklist of repeat spam offenders. As the note suggests contact your E-mail provider, which is websitewelcome.com

[Serafin96]

Thank you very much for your help!