Found a "hidden" file in the nginx/sites-available and nginx/site-enabled folders.
Deleted that and now I only have one nginx warning left.
When running 'sudo nginx -t' this is the result:
nginx: [warn] conflicting server name "keen.wtf" on 0.0.0.0:80, ignored
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
Ok i have now also removed the return 301 (line 4) in the nginx server block, I think it also conflicts with the rewrite in line 5.
And boom HTTPS works.
Next thing though, we still don't get to see a greenlock in firefox or chrome. It says something about the site only being partially secure. Any idea why that happens?
Now also fixed, our logo was still referring to a http link, removed the domain and just made it point to src="/assets/uploads/system/site-logo.png"
PS. any other tips or adjustments on the config files is also welcome