Maximum allowed attachment size not consistent

Maximum allowed attachment size not consistent

Greetings,

I just tried to send a message with a attachment of 21,25 MB. When I click on send in Applemail the Server tells the client it cannot handle the request because it exceeds the maximum attachment size of 25 MB. When I try to send it from the webmail however it tells me the maximum is 20MB instead. Obviously 20MB is the maximum allowed but I am curious why does the server communicate a 25 MB limit instead suddenly as exception handling.

Best regards,