The upgrade as an event went fine - with no errors in the upgrade process. After the upgrade logging into a mailbox or the admin tool works fine.

However, I can not send e-mail any longer. I get an error that the server is running slow and if I try again i get a message saying the messaging is in the queue. I've tried checking the logs, but I am not sure which ones will give me the best info.

Can someone help me walk through this issue?