Outlook 2007 keeps on prompting password / exchange 2013

Hi All,

Need a help.

We have moved 4 users from exchange 2007 to 2013 for some tests

-SSL cert installed on the new server
-outlook 2013 have no issues connecting to exchange 2013
-outlook 2007 can connect to exchange 2007 when creating the profile (after installing the necessary updates)
-outlook keeps on asking for password

-anybody encountered the same after switching to exchange 2013?

Thanks.