Issue: Lync federation not working.
Error: Test-CsFederatedPartner : A 504 (Server time-out) response was received from the network and the operation failed. See the exception details for more information.
Problem Statement:
Recently many Lync user complain regarding Lync IM not working with federated partner. However nothing was change however Lync federation got stopped working. When tested federation using Lync power shell it was giving above error.
Resolution:
Resolution was very simple and straight forward. However you must check below steps to find solution.
1. Try to telnet target Lync edge FQDN using 5061 port number.
2. Test-CsFederatedPartner –Target “Lync Server Pool FQDN” –Domain “Partner Domain name” and see the result. If you get above error means something with your federation partner Lync domain issue.
3. Try to nslookup on command prompt and type below.
Set q=srv
_sipfederationtls._tcp.domainname.com
You will get the exact edge FQDN and verify with access edge FQDN which you configured in External access, under allowed domain.
4. Go to Lync Control Panel and check the Lync Edge server FQDN and Domain name.
5. If Access Edge FQDN is not correct then change to correct one and test the Test-CsFederatedPartner command and see the result.
6. In my case Access edge FQDN was changed from federation partner. I have corrected the same and Lync federation started working.
Thank you.