So we are moving our way towards exchange 2013 and something odd keeps happening. When you setup the outlook client (either 2010 or 2013) the proxy authentication settings keep defaulting to basic despite the fact that I have ntlm setup on the cas. This then continues prompting users for a username and password. We could definitely teel them to click the remember this password button but I would like to make the upgrade as smooth as we possible can. Here are the settings:

ServerName                                   ExternalClientAuthenticationMethod      InternalClientAuthenticationMethod
----------                                   ----------------------------------      ----------------------------------
MAILHUB2                                                                   Ntlm                                    Ntlm
MAILHUB1                                                                  Basic                                    Ntlm

Mailhub1 is the 2010 frontend, mailhub2 is the new 2013. All DNS and autodiscovery is flowing through mailhub2. Thanks for you help!

Hi,

From your description, I recommend you use the following cmdlet to check if the ClientAuthenticationMethod is set to NTLM.

Get-OutlookAnywhere -Server "xxx" |fl ClientAuthenticationMethod

If no, you can use the Set-OutlookAnywhere -Name xxx -ClientAuthenticationMethod NTLM cmdlet to set it and check the result.

Hope this can be helpful to you.

Best regards,