We have an exchange  hybrid environment with Exchange 2013 on premises. we have 3 CAS servers and 3 Mailbox servers.

The CAS servers has configured with Citix Load balancer and authentication through ADFS.

The problem is that the Outlook clients are  frequently connecting and  disconnecting  for some users. After some time it will connect.

Meanwhile it will get an error proxy certificate error warning.

Anybody have any idea about this issue kindly share.

error

 

Hi

Did you import the SSL cert on the LB at all and are you doing SSL offloading?

yes we did

okay great

so you have the LB and ADFS which is additional hops to the servers.

As a test, if you add an entry to your local hosts file on your pc and point directly to the server do you get the disconnects?

Yes

I tried to connect directly to each CAS server  by modifying host file and it is not working at all.

Hi,

1 thing to be noted here is the Proxy Certificate Error warning.

I think all the 3 CAS Servers do not have the same settings OR the externalhostname/internalhostname are incorrect OR the Certificate installed on each of the CAS Server do not have the same certificate.

If there are network issues, the Outlook would attempt to connect to another Server where it would have a differnet Exchange Proxy Settings and hence you get the Warning errors.

I would like to know if the hostnames which I mentioned above are they same OR the certificate on each of the CAS Server are they same?

If certificate is not same, then you might run into issues like this. Hence I would suggest that you have a common certificate on all the 3 CAS Servers which can leverage the use of the attribute msstd/certprincipalname.

Do let me know your findings and we can figure it out the cause.

Karthick.

Dear Karthick

I checked all the CAS servers and which have same settings and certificate.

msstd/certprincipalname is same all CAS servers.

Thanks and Kind Regards

Hi,

Is there any related error message left when outlook disconnected ?
If the issue occurs again,I suggest we can do an Outlook connectivity test with https://testconnectivity.microsoft.com/   and see what went wrong.

On the problematic client side,we can try to re-create a new profile to test.

Regards,

David 

• Edited by David Wang_Microsoft contingent staff 2 hours 36 minutes ago

Hi,

Is there any related error message left when outlook disconnected ?
If the issue occurs again,I suggest we can do an Outlook connectivity test with https://testconnectivity.microsoft.com/   and see what went wrong.

On the problematic client side,we can try to re-create a new profile to test.

Regards,

David 

• Edited by David Wang_Microsoft contingent staff Friday, July 03, 2015 4:52 AM