Hi,
I have a 3 node Exchange 2013 (CU9) with a CAS Server and 2 node (MBX Servers) DAG which has been working fine for well over 8 months but during some Office 365 Preparation work, I noticed that Outlook clients (INTERNALLY only) were continually prompting for credentials (that were subsequently not accepted), to log onto their Exchange mailboxes.
By setting the IISAuthenticationMethods set to "Basic, Ntlm, Negotiate" (see below settings), I was able to get the EXISTING INTERNAL outlook clients to connect (they just ignore the credentials request)
ExternalClientAuthenticationMethod : Basic
InternalClientAuthenticationMethod : Ntlm
ExternalClientsRequireSsl : True
InternalClientsRequireSsl : True
IISAuthenticationMethods : {Basic, Ntlm, Negotiate}
but I can still NOT set up new profiles. Autodiscovery should obviously find the CAS server and return the mailbox GUID but it resolves to the Mailbox Node Server instead and then refuses to connect.
I have a different internal to external Domain so have used an autodiscover SRV setting on my internal DNS that points to the external name on my SSL certificate (eg mail.domain.com) and this all used to work so a bit stumped as to what to troubleshoot.
John Philipson