Why is my email attachment size limit not updating in Exchange?

Check the settings on the client side Outlook or other access-point used to access the email account.
Ensure the message size limit set in the Exchange Account matches the limit set in the client.
Check the server side settings for the Exchange environment to attest the correct message size limit settings.
Attempt to adjust appropriate message size limit values, if needed, in the appropriate areas.
If adjusting the message size limit in the Exchange server fails, check and remove any restrictions for mailbox or group policies in Active Directory.