I have six email messages that are stuck in my Outbox.

I would consider that the problem might be with my email service provider (ESP). However, the emails have been sent from different ESPs with the same result - that they have not been delivered. I am able to receive message and the connection doctor indicates that all connections are good. Yet, I am unable to have these messages delivered. This is a recurring (but intermittent) problem. The problem usually resolves itself in a few hours. However, this time is taking a bit longer - as my last message was sent this time yesterday.