I have a Exchange 2010 server on Windows server 2008 using outlook anywhere. I have to start a new question because the old one was misdirected but you can read my finding there http://www.experts-exchange.com/Software/Server_Software/Email_Servers/Exchange/Q_26921524.html I have a problem with some exchange accounts failing during authentication with outlook anywhere when outside of the office lan (internal outlook anywhere always works). I ran a outlook.exe /dcdiag and these accounts wont even connect properly just remain on connecting. (i ran the test on a external network). I used the exchange connectivity tester website to try one of the problem account outside of my local and my account. When i run MY account though the exchange connectivity tester it goes though the test fine and connects without a problem. I only get a warning "The Referral service returned generic error 0x80004005. This many mean that encryption is required. ExRCA is trying again with encryption" - It then tries again with encryption and no problem. However when i try a account that outlook anywhere does not work i get one of two errors. At first i got the Testing SSL mutual authentication with the RPC proxy server. Verification of mutual authentication failed. Tell me more about this issue and how to resolve it Additional Details The certificate common name *.brookskushman.com doesn't validate against the mutual authentication string that was provided: msstd:webmail.brookskushman.com I figured out this probably happened because i am using a wildcard certificate. No problem i went ahead and Set-OutlookProvider -Identity EXPR and WEB to my common name certifcate msstd:*.brookskushman.com , and also entered the certifcate name manually when using the conncitivty tester. When i do that i get a NEW error! A Web exception occurred because an HTTP 401 - Unauthorized response was received from Unknown. How can one account work fine without a problem and another get a RPC Proxy can't be pinged when using outlook anywhere?! This problem only occurs for some accounts outside the office lan. Also some of the accounts that are having the RPC ping problem occur intermediately. some account will be fine for a week and then suddenly not work. All the problem email accounts work fine internally as expected when configured for outlook anywhere. Before you jump and say wrong settings during mail profile setup, let me assure you its all correct. So what the heck? Note: My exchange server has all roles installed on the same server and i am not using a edge server, insisted i have email coming into my gateway a baraccuda spam/firewall and then dumping to the exchange connector.