Use correct variable name in fail text

public/views/index-template.html

@@ -178,7 +178,7 @@
       </p>
       <p>
         1. This could be caused by your reverse proxy settings.<br /><br />
-        2. If you host grafana under subpath make sure your grafana.ini root_path setting includes subpath<br /> <br />
+        2. If you host grafana under subpath make sure your grafana.ini root_url setting includes subpath<br /> <br />
         3. If you have a local dev build make sure you build frontend using: npm run dev, npm run watch, or npm run
         build<br /> <br />
         4. Sometimes restarting grafana-server can help<br />