Hi All, New to 3CX and trying to setup a lab evironment for testing. We have a boat load of Polcom VVX410's from other cloud PBX services that if I can get to work with 3CX would give me some good options to move over to 3CX. Current setup is: - 3CX Pro running in Google Cloud - SIP Trunk configured - 1 extension provisioned and working using 3CX Client and Windows Client - 1 extension provisioned for Polycom VVX410 I have read the Polycom article here. As we are running in Google Cloud I cannot provision locally through LAN provisioning URL. I guess I could create VPN link to Google Cloud but wanted to avoid this as handsets will potentially be in homes etc. where I have no control of. I set the provisioning interface to the external NIC / hostname. I have read the articles about Polycom handsets not liking the Lets Encrypt certificates therefore I enabled HTTP / Port 80 on the VM Instance. I have factory reset the polycom (trying different levels of F/W along the way). I am able to provision the extension if I go into the Web GUI of the handset and paste the provisioning server URL in there. The handset then pulls down the config details, e.g. 3CX wallpaper, extension number, name etc. but the handset fails to register the SIP line and I get the error "Line unregistered" / "URL Calling Disabled". I feel I'm so close but missing something simple hopefully? Can anyone advise?