set up outlook 2007

Hello,

I moves all mailboxes from 2010 to 2013.

When I saw my outlook 2007 exchange setting look like

{a serial number}@mydomain.com

Then I changed to server name then my outlook cannot connect to exchange server.

"you must connect to Microsoft Exchange with the current profile before you can synchronize your folders with your offine folder file."

Thanks

Newbie