Recently I assisted a customer that had removed TMG from their environment and installed WAP 2019 for the reverse proxy. As we all know mobile devices are being used more and more in corporations and with security being a big concern its time to get some of the older technologies updated.
The issue was not with the installation of the WAP server. This issue in particular had to with the Android devices. When logging into Skype the first time everything went as planned. However, when logging out and back in we would see errors stating trying to connect to server and presence stuck at updating….
Reviewing Skype for Business server side logs and client logs we get different errors. The server side logs show a 401 and for whatever reason the client (Droid) was getting a 500. iOS worked just fine.
After some research I found there is a know issue currently with the WAP 2019 server. Server 2019 has HTTP2 enabled by default and this does not support Windows Auth.
To fix this simlpy set to 0 on HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp\EnableDefaultHttp2 on all the 2019 servers and reboot/test.
More information can be found here