Hi ,
I just stumble on that problem and bang my head on it for a few hours .The solution i have is really not end user solution ,but i think i worth sharing for other admin having the issue
As the corporate system admin , during our exchange migration from exc2010 to 2013 , we did remove imap/pop/smtp old fashion way and move on too full https/rpc and ews setup , and we add move on to hardware ssl offloading with our loadbalancer .
Since everything was working find for all my windows/mac outlook client , thunderbird,entourage ,etc .
We did not realy supected anything network wise .
But after a few hour off tcp/ip profiling ,etc .
We found out that during the ntlm security handshake step 2 was failling with a connection error code i think it was 600 , in the message log from the MACbook , followed by a drop connection . after few test to see where the connection was reset .We found out it was drop by load balancer with a timeout errorr (waiting for initnal client request) just like SYN with no ack . It is drop by the native system of the appliance or the SNORT system that is connected into it we dont know yet.
But the fix was switch back to software iis ssl management ,that remove the unencrypt ,inspect ,rencrypt done by the loadbalancer .
There something there the mac mail client does not like , but most likely to be the add x-forward header
to a faulty ntlm implemantation in mac lion up just like the new mac smb ... can be alot of thing .
So to make it work
Open port 80/443
Full ssl support done on the iis cas server. no hardware ssl offloading or at least with kemp lm-2500, iam yet to try with netscaler or f5 sytem
Configure ews organisaton policy by default they seem not to be.
now i have all mac world client working fine .
as a extra during our test phase we found out that enabling digest login for the EWS folder will break the http conection mode for outlook 2011 for mac .