error message keeps popping up

I keep seeing this error message pop. I have no draft message waiting to be sent. Is there some place else where unsent messages are stored that be causing this?

Hi Steve, the message should be located in your Outbox folder, try to enable smart folder outbox, to enable smart folders please navigate to Tools > Settings > General, and when the option is enabled right click smart folders and select Display > Outbox.

Hopefully the message should be shown there.

Hope this helps,