Incoming connection failed to receive mail. Queue Full

[hisyam22]

Hello,

I got a problem with log that showing "Incoming connection (ICID 5686180) failed to receive mail. Queue Full". This log is repeated and the email is not sent. I use appliance C680 model. And also this Ironport is used to sent for Yahoo domain. Corrective action that i take is increase size of destination control for Yahoo domain but I still not sure with the action. 

Hope you can help me to figure this out

[ppreenja]

Hello Hisyam22,

The error message you can see on the Appliance indicates that the Queue for the messages is completely full and so the appliance is not able to store new messages. With this, they go into a Resource Conservation Mode to make sure that no further messages need to get stored in the already full queue.

The resource conservation mode is a self-protective mode that the appliance enters when there is a short on internal system resources, it happens when the rate of coming messages is higher than the delivery rate for a long period of time so there will be no space to store more messages, the appliance will slow down the process of receiving messages until the balance is back between the incoming and the delivered messages.

Resource Conservation Mode always happens when there is a misbalance between the receiving and the delivery side of the appliance. The appliance then needs to buffer the messages due to failure to deliver them as fast as receiving them.

To check on the rate at which the incoming emails are received is configured in the mail flow policies and for the checking, on the rate for the destination domain, you can configure the same in the destination controls.
Please find below the articles which will be able to provide more information with regards to same:
https://www.cisco.com/c/en/us/support/docs/security/email-security-appliance/118177-technote-esa-00.html
https://www.cisco.com/c/en/us/support/docs/security/email-security-appliance/118573-technote-esa-00.html
https://www.cisco.com/c/en/us/support/docs/security/email-security-appliance/118179-configure-esa-00.html

Since you have mentioned regarding the yahoo domain which should be outgoing email and hence I would request you to check on the rate for the "RELAYED" mail flow policy rate configuration and try to adjust the connection for the yahoo domain in destination control accordingly.

I hope the above information is helpful.

Cheers,
Pratham