What is my email attachment size limit?
Our maximum attachment size is 20 MB for POP mailboxes and 100 MB for Full Exchange mailboxes. This matches the typical maximum attachment size supported by most mail clients.
Please note that this includes encoding overhead so attaching a 20 MB zip file will likely fail as encoding increases the size of most files.
Also the receiving system also will most likely have a message size limit which will be applied as well.