Message Blocked | 550 Envelope blocked - User Entry

[Kirubakaran]

Hello All,

Our GTM emails are getting blocked by few domains that are using mimecast's email security it seems. Following is the bounce back email response from those receivers, 

Message blocked
Your message to (username@domain.com) has been blocked. See technical details below for more information.

The response from the remote server was:
550 Envelope blocked - User Entry - mimecast community [Z23cWiIxOGidUNl_6-iWng.us321]

Any help? 

[KAM]

@Kirubakaran the mimecast error implies that there was a specific entry to block your emails.

If this isn't a cold email, I would recommend you call the recipient and confirm things are ok.  

-KAM

[Kirubakaran]

Hi @KAM 

Thank you for your response. We received the same bounce-back message from three different domains when our GTM team attempted to reach out to customers. Some of these emails were follow-ups and meeting scheduling requests. Therefore, I believe we need to investigate the issue from our end as well.

We will definitely contact the recipients to check this. Thank you.