Message exceeds the maximum supported size

Earlier this week attempted to send email with 4 small attachments - not accepted as being too large.
Since then whenever I Receive or Send an email message my system freezes and I get a red triangle waring to the effect that message is too large. Also advised to go to Settings but unclear as to what I should change there. I get this each time even with one line emails

message under red triangle reads
[Exchange Web Services]Sending email failed due to the following error: The message exceeds the maximum supported size., The message exceeds the maximum supported size.
Calibri (Body)

There is a setting in Menu > Settings > General > Confirmations, to notify if sending messages above a certain size. Find out from your email provider what that is, then tick this option, and set the size. The default setting is 10MB which is the average that most providers allow recipients to receive.

If the previous message is stuck in eM Client, select Menu > Settings > General > General > Show Local Folders, then go to the Local Folder Outbox and delete it.