Thanks for the reply. I managed to solved the issue. I was inspired by this thread: Debugging help - Nextcloud- coolwsd servers - #8 by FamousL
Turns out, I’ve set Header set Content-Security-Policy "frame-ancestors 'self';" in my apache config as a security measure. Previously with only nextcloud running on the server, this works just fine. But not with Collabora added to the setup. Now I’ve commented out this config line, I can finally open documents.
The tricky part of my issue was that none of the logs show any errors, neither nextcloud nor CODE nor apache told me something went wrong. CODE just had one warning convert-to: Requesting address is denied: ***.***.**.** but it was not relevant.
The config in question is a line provided by the apache installation in etc/apache2//conf-enabled/security.conf. Do you know if I can somehow modify this line to make it secure against other types of attacks while enabling CODE access?
Regards,
William