Server authentication certificate error - HTML client windows server 2019

Question

Hiya,

I am using the RDweb client, when attempting to connect to a remote computer, I receive the following error:

Your session ended because an unexpected server authentication certificate was received from the remote PC. Ask your admin or tech support for help.

I have done a lot of searching around to find an answer, but without prevailing.

It turns out my old cert did expire, so I replaced it with a wildcard cert which is already in use elsewhere in my system (same domain).

I have tried running Import-RDWebClientBrokerCert with the new .cer certificate, and now Get-RDWebClientBrokerCert shows the correct certificate. However, the error still occurs.

I have tried restarting the relevant services and restarting the whole machine. Normal RD connections using RDP work fine, just not in the HTML web client.

I have tried clearing the browsers cache, and using incognito mode and different machines, but the Certificate Information is still returning the old certificate, not the new one.

Any help would be greatly appreciated, thank you!