Chrome Remote Desktop - enabling curtain mode results in instant disconnects?

[Garacesh]

Weird one here..

 

With Curtain Mode disabled (so Chrome RD runs more like remote assistance than remote desktop) everything works fine. But of course, anybody in the room could see the session live, so I'm this isn't really useful.

As soon as I enable Curtain Mode, it gets to putting in the PIN then boots me off. It's definitely making a connection, because if I purposely put the PIN in wrong it says so.

 

This happens whether I apply the GPO at

Computer Policies\Policies\Administrative Templates\Google Chrome\Remote access\Enable Curtaining of remote access hosts (Enabled)

 

Or the corresponding registry keys

HKLM\SOFTWARE\Policies\Google\Chrome\RemoteAccessHostRequireCurtain (REG_DWORD, 00000001)

HKLM\SOFTWARE\WOW6432Node\Policies\Google\Chrome\RemoteAccessHostRequireCurtain (REG_DWORD, 00000001)

 

Or both.

 

Unfortunately using actual RDS isn't an option at the moment as our gateway server is unlicensed and our licensing reseller is being... slow. I assume they're still understaffed because COVID

Alternatively, is there anything else out there that can be used in the interim?