unable to sign in with auto configuration

[Thai_Lam]

Hi,

I am having difficulty to sign in sfb on premises with automatic configuration. Manual works fine. The following gathered from fiddler.

We can see it is resolving lyncdiscoverinternal.domain.com (autodiscover) and it was tunnel to lyncwebint.domain.com. However it is not directing to hostname lyncwenint.domain.com. It just stuck on tunneling, failed and continue with other autodiscover method (autodiscover remaining)

fiddlerautodiscoverautodiscover remaining

The fiddler has https decryption enabled. What is the likely cause here? Thanks!

[#2]

@Thai_Lam 

Try to browse that manually from web browser - Anything changed on LB or DNS? 

https://lyncwebint.domain.com/autodiscover/autodiscover.svc - if client internal

[#3]

@rameshram18 

The autodiscover page is accessible

[#4]

if i am trying the manual configuration it works. which is sip.domain:5061 and sip.domian:443
is it possible for me to register a cname from sip.domian2 to sip.domain? likely will this work? will it go port 5061 or 443?