Also in 2009 I wrote an article called "Outlook Anywhere keeps prompting for Password" which can be found at the following URL:
In this blog post I am going to touch on these two topics a bit further as this issue will impact many organisations moving to Exchange 2013 for those still running Windows XP (despite the fact it is no longer supported) seeming Exchange 2013 only supports RPC over HTTP or MAPI over HTTP (out of scope for this article). To recap what I wrote about in the previous articles 5 years ago, for RPC over HTTP(s) aka Outlook Anywhere to work on any version of the Outlook Client on the XP, the MSSTD value must match the "Common Name" on the certificate. What am I talking about? Well let me show you...
The MSSTD is specified under "Only connect to proxy servers that have this principal name in their certificate" which can be found within Outlook under Account Settings, Open the Account, More Settings, Connection Tab and finally Exchange Proxy Settings.