Check this thread for more insight - https://serverfault.com/questions/269373/exchange-2010-and-outlook-2010-requesting-password-every-time-it-starts
After the public database is deleted in exchange 2010, users in the domain need to enter the user name and password every time they open Outlook
chenxiling
21
Reputation points
After exchange 2010 deletes the public database, users in the domain need to enter the user name and password every time they open Outlook. After exchange 2010, client Outlook 2007, and exchange 2010 delete the public database, client Outlook 2007 needs to enter the user name password every time it is opened. The connection status cache is https. After Outlook is closed, users do not need to enter the user name and password when it is opened normally. The connection status is tcp/ip, Everything is normal before the exchange 2010 public database is deleted