Emails bloqued by SEP 11.x

Hello,

I am experincing severe issues because some of my endpoints are experiencing problems when sending emails.

They are being blocked by SEP presenting the message:

- "Your email message was unable to be sent because your mail server rejected the sender: 421 4.7.0 dellbld11.srv.portugalmail.net Error: too many errors"

Please do give some urgent assistance.

Best regards

Ricardo Silva