ERROR_CODE :554, ERROR_CODE :5.7.1 Unknown Sender in Local Domain . HEEEELP PLS

ERROR_CODE :554, ERROR_CODE :5.7.1 Unknown Sender in Local Domain . HEEEELP PLS

HELP, HOW CAN I FIX THIS PROBLEM , I CANT SEND EMAIL NEITHER RECIVE IT, HERE A SCREENSHOOT
, MY DOMAIN IS WWW.SERVSUR.COM  AND THE MAN ACCOUNT OF ZOHO IS GRUPOSERVSUR@SERVSUR.COM, THANKS PLS HELP :(