Warnings in the configuration Nextcloud

Ah I think I know the issue. Can you show:

cat /etc/nginx/sites-available/default

EDIT: From Nginx docs:

There could be several add_header directives. These directives are inherited from the previous configuration level if and only if there are no add_header directives defined on the current level.

So we need to add the header to the Nextcloud config explicitly. This is what I don’t like about Nginx. Not intuitive, leads to much duplicate directives, and it this does not apply to headers only (but not everything, inconsistent), but other directives as well, making it difficult to find reasons/issues by times, at least for me.