I have Nextcloud installed on shared hosting and the nextcloud office module and the CODE, but if I try to create a document or open one it just loads forever. In the nextcloud log it just says:
Fetched capabilities endpoint from https://nube.compusya.com/apps/richdocumentscode/proxy.php?req=/hosting/capabilities in 0.22 seconds
Hey @julbroa. Welcome to the forum + thanks for the question. 
I did a search for your “Fetched capabilities endpoint” error and came across this topic on Nextcloud’s forums from earlier this year:
It looks like Post #3 pointed towards a Nextcloud Wiki article which helped solve some of their specific setup issues:
Let us know if that solves your issue (and what steps you did to fix it!).