Seem to be having an issue with Windows Clients (4.7 & 4.8) logging into internal desktop pools (2016 RDS Manual) enabling the proxy server in IE. Results in users not being able to access anything on the Web (as you'd expect), until they remove the proxy setting.
Logging in via HTML, or another OS (ThinOS) does not have this same behaviour and I have no proxy settings configured on the RDS side via GPO. There is also no proxy server conigured within IE on the Windows client.
This only happens when Windows clients connect in. Not been able to find any documentation stating a reason for this behaviour so hopefully someone else might be able to give me a quick fix for it.
VMWare Horizon 7.4 (7400497)