I am using Outlook on my iMac. I am getting a message every visit to the server that an email message 5.4.3 is too big. It has now been trying for three weeks. I cannot find any such message or any oversize message sent in that period. I have deleted all the Sent messages but still it tries every ten minutes and sends me back the same message. I do not have an Outbox showing.
How do I stop this happening, please ? How do I generate an Outbox