Hey guys,

at first I want to say sorry, because I guess here are some similar threads like mine, but unfortunately I have not found a proper match.

I have set up a small Lync environment with one FE and one Edge, both are standard edition servers. As reverse proxy we are using the Sophos UTM 9.3

Internally Lync is working smoothly, all services are available and automatic logon is working as well. Unfortunately from external it looks different. The mobile app for Android or iOS is working with automatic logon, but not with the Lync Office application. If I try to logon I get an Em saying that the server is not available.

Running the Remote Connectivity Analyzer I get "The endpoint was unable to register. See the ErrorCode for specific reason." Error code 504 leading to this not much sayin' page...

Link

After that I found that checklist and executed all checkups...

Link
I can say that all nslookups work and all necessary ports are open. BTW we are using a wildcard certificate, I know it is not that recommend, but is working anyway with some small exceptions.

It would be nice if you could give me a hint where to search for a configuration issue.
For sure if needed I will post some more config details.

Thanks in advance.

Kind regards,

Chris

• Edited by woelki 10 hours 3 minutes ago