Remote Desktop via Azure Application Proxy

[ITGURU]

sorry to bring up an old thread! However i'm 99% there with getting RDweb working through azure proxy and wondered if someone could help me please, who has it successfully working

So far

- I can go to the https:// msappproxy url and authenticate via office 365

- i get the local server rd login page and the user can login successfully

- i click on an APP ,in the html web client

- i get the error below.

 

not sure where I need to check/change settings or what to check?

I've followed multiple online guides of which all seem to be all part of the step by step required.