I have an issue with MEG 7.6 regarding the message size limit. I've modified the message size in my Inbound Email Policy to 40000KB both in the message size and attachment size and I tested sending from my gmail account an email of 22MB which seems to be blocked with the reason "Message size exceeds the fixed maximum message size" error.
Is there other setting I should do except in the Email Policy section?
What is your size set it to on your mail servers? Exchange has a place for limits as well. Are you sure it wasn't a message from GMAIL? I don't think they allow a message size like that.