Trying to access the webservices from the internal frontendpool on port 443. Tcp port 5061 on edge access server is typically used for federation and not relevant for our sign-process. Trying to access the edge access server and tcp port 443 which uses desktop client for sign-in. The edge access server also had published tcp port 5061 for federation. Now we can test if we can establish a tcp connection to the webservices which listens on tcp port 443 and the edge access server also on tcp port 443 for sip signalling which is used by our external desktop clients for authentification. So the first thing was testing if DNS is working and I will get the correct IPs for the Webservices FQDN and the Edge Access Server FQDN.Įverything was fine and I got the correct IPs. Here you can see the sign-in attempt from external at the affected client.īecause of this error message the first thought was network connectivity issues. Internal the affected clients can sign-in without any issues. So this is always an ungrateful situation and costs a lot of time digging into it, especially since the skype for business sign-in process is very complex. Recently I had to deal with sign-in issues a few external sfb desktop clients on a non-regular basis experience.

Skype for business login logs