Basically, as far as I can tell, your issue stems around the reverse_proxy and its connection to the collabora server
@qubit2022 Here is another post from this forum
@kevdog It is the Collabora Online App 3.6.0 Version, not the docker version. https://apps.nextcloud.com/apps/richdocuments
The solution is to set the following entry in Apache VirtualHost. https://nextcloud.com/de/collaboraonline/
# Endpoint with information about availability of various features
ProxyPass /hosting/capabilities https://127.0.0.1:9980/hosting/capabilities retry=0
ProxyPassReverse /hosting/capabilities https://127.0.0.1:9980/hosting/capabilities
This is how the C…
And here is another with a guide on how to set it up using Ubuntu, Collabora Code and Docker
1.Overview
This is a general guide to setting up a functional Nextcloud instance using Ubuntu Server 18.04.3, Docker CE, Docker-Compose, Collabora CODE, and an Apache reverse proxy. By the end (and as of writing), this setup will have an A+ rating on Nextcloud Security Scan and Qualys SSL Server Test and a valid, self-updating certificate from Let’s Encrypt. I will also cover how to update everything.
I will do my best to plainly emphasize things that you will need to change, but it will mainly…
@qubit2022 The guide above from this forum shows an example of turning off ssl/tls insecure verification for Apache2SSLProxyVerify None
so my recommendation is to google around a bit for that and I believe you will solve this 