I have Office 365 on a Windows 10 PC. I have 2 email accounts that where working fine. I tried or installed a third from work that was not authorized an I think it made it the default in Microsoft Exchange. I cannot open my outlook and but I keep getting asked for password and it has the new email address on top of the password box. I have tried to log into this exchange account but it tells me I an not authorized to do so. How can I get back to my previous outlook?