Mail delivery error

Received a complaint from a ticket submitter that they hadn’t received any email notification when correspondence had been added to the ticket. In examining the ticket, it did record two failed attempts at message delivery as indicated below:

Upon examining the maillogs it appears there was an issue with interpreting the 2 attachments within the ticket. The maximum allowable attachment size is set to 30MB, and the larger of the 2 attachments is well below that limit at 27MB. The attachments were able to be added, but apparently something about them prevented the system from sending out a correspondence notification. This is what the logs indicated:

Nov 17 08:33:42 rt postfix/postdrop[21657]: warning: uid=48: File too large
Nov 17 08:33:42 rt postfix/sendmail[21656]: fatal: apache(48): message file too big
Nov 17 08:33:49 rt postfix/postdrop[21659]: warning: uid=48: File too large
Nov 17 08:33:49 rt postfix/sendmail[21658]: fatal: apache(48): message file too big

If that is coming from Postfix then there must be some config set in the email toolchain that has a maximum value set as well. You can check for message_size_limit in your Postfix config.

The appliance doesn’t try to send out the attachments as part of the correspondence trigger though does it?

That limit is set to 12240000

Are you relaying to another email server?

I think mail attachments are pretty much always base64-encoded, which inflates their size substantially (~35%). See also Base64 - Wikipedia