Have you managed to resolve this, I have the same problem. See here: https://help.nextcloud.com/t/cant-connect-to-collabora-online/1878/11?u=steven_horner
I haven’t been able to fix it yet 
Have you managed to resolve this, I have the same problem. See here: https://help.nextcloud.com/t/cant-connect-to-collabora-online/1878/11?u=steven_horner
I haven’t been able to fix it yet