I have been running an Exchange 2007 server for several years without any problems. For the past couple days (since 6/21) the server will no longer receive messages. As far as I know no changes were made to the server. I have IGetMail running on the server to collect message from POP3 accounts and it is telling me that it can not send message to the email server. I tried sending a test message from my gmail account and query the server to use the Message Tracking tool but it does not show up. According to the Queue Viewer there are also no messages.
I do have a warning in the event viewer stating "An internal transport certificate expired". It looks like I started getting these error messages on the 14th. I ran the New-ExchangeCertificate cmdlet but I am still getting errors / warnings indicating the certificate for the local system is about to expire or already expired. I am going to try to reboot the machine.