CORS issue, how to work around it with Nginx Proxy Manager

First comment:

You need to edit proxy settings for uptime kuma, under Custom Locations add a new location with location as / and then enter your scheme/hostname/port for uptime kuma. Then go to the gear icon besides location and enter add_header 'Access-Control-Allow-Origin' *; and then save.

Made static cms work with gitea/forgejo.