Sangoma Connect Desktop Client log in issues with FQDN

I’m setting Sangoma Connect up with the 2 free licenses to test before going live.
I’ve been following the instructions at How+to+Setup+Sangoma+Phone+Desktop+on+the+PBX
I’m having issues with the Desktop Client logging in with my FQDN and port 6443. I can get it to work with my IPv4 address.
My internal DNS server points to the PBX and it has a reverse ptr record as well. I can ping my FQDN from my desktop fine, and it resolves to the PBX internal IP
The port is set to 6443 in the Port Management.
As per the trouble shooting when I test [Sangoma Phone Desktop Client Host Address]:[Sangoma Phone Desktop Client Service Port]/rtapiws
It comes up with Bad Request like it should.
I also tried to run the Desktop Client with the flags --DEBUG --PRERELEASE and the console window doesn’t open for me. So not sure how to see that.
The Mobile app seems to work both internally and externally.
I have a cert created with LetsEncrypt and have inputted it in all the spots laid out by the instructions.
Just not sure what I’m missing to make the Desktop client work with my FQDN.

I have been able to get the Desktop Client into Debug mode and I’m getting the following:
WebSocket connection to ‘wss://my.fqdn.ca:6443/rtapiws’ failed:

I replaced my actual domain with my.fqdn