Gitlab begind nginx proxy, home page not displayed (404)

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I have gitlab running under plesk and I was using it under apache24 proxypass. I couldn’t get the web terminal working, so I switched the proxy to nginx.

Now, all seems good and it’s running and everything is working, except that the home page (/) is not being displayed, I get a 404 there. There is a unmatched_route error shown in the logs.

==> /var/log/gitlab/gitlab-rails/production.log <==
Started GET "/index.html" for 62.167.83.226 at 2020-02-17 16:18:36 +0100
Processing by ApplicationController#route_not_found as HTML
  Parameters: {"unmatched_route"=>"index"}
Completed 404 Not Found in 74ms (Views: 6.1ms | ActiveRecord: 5.0ms | Elasticsearch: 0.0ms)
Started GET "/favicon.ico" for 62.167.83.226 at 2020-02-17 16:18:36 +0100

==> /var/log/gitlab/gitlab-rails/production_json.log <==
{"method":"GET","path":"/index.html","format":"html","controller":"ApplicationController","action":"route_not_found","status":404,"duration":73.62,"view":6.11,"db":4.96,"time":"2020-02-17T15:18:36.721Z","params":[{"key":"unmatched_route","value":"index"}],"remote_ip":"62.167.83.226","user_id":2,"username":"andy","ua":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.100 Safari/537.36","queue_duration":3.75,"correlation_id":"tG4RpGxXYD7","cpu_s":0.2080945199999995}

My Proxy code:

location / {
	client_max_body_size 0;
	gzip off;

	## https://github.com/gitlabhq/gitlabhq/issues/694
	## Some requests take more than 30 seconds.
	proxy_read_timeout      300;
	proxy_connect_timeout   300;
	proxy_redirect          off;

	proxy_http_version 1.1;

	proxy_set_header    Host                $http_host;
	proxy_set_header    X-Real-IP           $remote_addr;
	proxy_set_header    X-Forwarded-Ssl     on;
	proxy_set_header    X-Forwarded-For     $proxy_add_x_forwarded_for;
	proxy_set_header    X-Forwarded-Proto   $scheme;
	proxy_pass http://127.0.0.1:8081;

	proxy_set_header Upgrade $http_upgrade;
	proxy_set_header Connection "Upgrade";
}

Any ideas?