- my enviornment is a 2010 - 2003 co-existing . everything migrated to 2010 and two-way route between 2003 and 2010 is removed. all outlooks are connected to 2010 server.
- In order to decomission 2003 exchange server , I decided to stop its services for a couple of days before I uninstall it completely . just in-case something that I missed to migrate.
- I think we are getting these prompts because of stopping 2003 services, I did stop the services yesterday and right after that some users got autodiscover.company.com logon prompt. If the cancel the prompt , outlook connects to exchange 2010.
- 2010 exchange is in a different subnet but it's accessible. 2003 exchange is in the same subnet as clients.