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Ninja03
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Outlook clients not connecting to Exchange 2013

I am having a lot of sporadic problems with outlook connectivity to exchange 2013.  Right now I can't get my outlook to connect.  It is failing the autodiscover test, giving me a GetLastError = 12002 httpstatus=0.  It keeps prompting for credentials, but doesn't make any difference when i enter them.

However if I go to the Microsoft Remote Connectivity tool it will succeed on the Outlook Anywhere test by using a SRV record lookup.  

Also, Active sync appears to be working correctly.  However, I cannot connect to the OWA, but other users can.  When I try to go there I get saying that "The website declined to show this page".  

On the ECP i've got Outlook Anywhere authentication set to NTLM.  Default website is set to anonymous auth, SSL required.  

Not really sure where to even begin, but i need to find a solution quickly.  Any help greatly appreciated!
ExchangeMicrosoft ApplicationsOutlook

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Simon Butler (Sembee)

8/22/2022 - Mon
ASKER CERTIFIED SOLUTION
Will Szymkowski

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Ninja03

ASKER
Hi Will,

We only have a single name cert for "mail.mycompany.com".  However I was under the impression that this could be made to work without having a SAN?

Both external and internal clients are set to work "mail.mycompany.com" using NTLM auth on the exchange side.

In IIS the default site is set to allow anonymous auth and require ssl.  
The OWA virtual directory is set up with Basic Auth.  All my clients are Outlook 2013.  

On certain computers I can log into OWA with my account no problems, on others I can't even get the page to display?

Found something else interesting.  On computers that connect to exchange if I ping "mail.mycompany.com" it returns the server's internal IP.  On clients that cannot connect it returns the external ip, but then times out.  

On one of the clients with this issue, i manually added a record to the host file pointing "mail.mycompany.com" to the internal ip of the server.  After this, the client could connect to both OWA and exchange through outlook.
Simon Butler (Sembee)

Sounds like your DNS settings aren't correct, or there is a replication issue.
Ensure that all clients are using the AD domain controllers for DNS only. No external DNS servers should be listed anywhere.
If the workstations are on DHCP, then check the settings are correct there.

As you have seen, resolving to the external IP address will confuse your firewall/router and the traffic doesn't get back in.

Simon.
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