In years past, I could easily attach a file to and Outlook 13 email and send. Now I receive an error message saying "the file you're attaching is bigger than server allows. Try putting the file in a shared location and sending a link." WHY?
Interestingly, if I go to the file/picture and right click and send by email, I have no problem.
Please let us know the total size of the attachment to double-confirm it. Also if no matter the size, all the attachments always trigger this issue? If so, please share the detailed reproduce steps with us to test it on our lab? If not, it may be a temporary issue, please update Outlook client to check it. In this scenario, you can provide us the reproduce steps as well.