I had this issue too. As an addendum we were able to send emails to our own staff but no outside parties.

Through a chat with a live agent at Sage 50 Support I found out that a recent Windows update 'broke' the MAPI function between Outlook and Sage 50. The first solution offered was to ensure that I only had one email account set up in Outlook. I had two accounts set up, so I deleted the lesser-used account (leaving only one account set up) and this fixed the issue for me.

The support agent also said to delete and re-install the email account in Outlook to repair the MAPI function. We didn't need to do this after deleting the second account from Outlook, but this would have been our next step if the issue still persisted.

You are correct, removing the second account worked. But once I add the second account back in the issue seems to return. Making a new outlook profile and adding both accounts doesn't seem to solve the issue either. There must be a fix without having to remove the second account.

You are correct, removing the second account worked. But once I add the second account back in the issue seems to return. Making a new outlook profile and adding both accounts doesn't seem to solve the issue either. There must be a fix without having to remove the second account.