Messaging Gateway

We are always fighting issues with receiving emails from mimecast servers.

The error we see is Rejected by MTA. 

An IP lookup shows connection class 4 with all emails being differed.

the sender is getting this message.

could not be delivered. The problem appears to be :
-- Recipient server unavailable or busy

Additional information follows :
-- 4.3.2 try again later

This condition occurred after 30 attempt(s) to deliver over a period of 92 hour(s).

If you sent the email to multiple recipients, you will receive one of these messages for each one which failed delivery,  otherwise they have been sent.

This enhanced system notification has been specially generated for you by Mimecast - the brain for your email.

Any useful suggestions?

Hi,

Usually i found these entries in case of SMG blocking the connection at firewall level because of local or global block list, conn classification etc.

In your case i would guess its conneciton classification - so too many connecitons within your configured timeframe.

Suggestions:

- check your connection classification settings, any modifications made there?

- temp. whitelisting the ips

- temp. turn off conn classification

Temporary steps should only be done to get the cause of non-delivery.

Thomas