Gerrit plugin-manager doesn't show plugins - gerrit

Question

I have a Gerrit v2.15 on a linux machine and I'm the administrator in Gerrit.
I installed the Gerrit plugin-manager under gerrit/plugins with command :
wget https://gerrit-ci.gerritforge.com/view/Plugins-stable-2.15/job/plugin-plugin-manager-bazel-master-stable-2.15/lastSuccessfulBuild/artifact/bazel-genfiles/plugins/plugin-manager/plugin-manager.jar
But nothing uploads in Gerrit UI in tab Plugins. I only see the Installed, as before.
In gerrit/logs/error.log I can read out the following:
[2018-06-15 08:54:26,366] [main] INFO com.google.gerrit.server.plugins.PluginLoader : Loaded plugin plugin-manager, version v2.15-1-g27c3d2935d
[2018-06-15 08:54:26,367] [plugin-manager-preloader] INFO com.googlesource.gerrit.plugins.manager.OnStartStop : Start-up: pre-loading list of plugins from registry
[2018-06-15 08:54:26,902] [main] INFO com.google.gerrit.server.git.GarbageCollectionRunner : Ignoring missing gc schedule configuration
[2018-06-15 08:54:26,902] [main] INFO com.google.gerrit.server.config.ScheduleConfig : accountDeactivation schedule parameter "accountDeactivation.interval" is not configured
[2018-06-15 08:54:26,902] [main] INFO com.google.gerrit.server.change.ChangeCleanupRunner : Ignoring missing changeCleanup schedule configuration
[2018-06-15 08:54:26,946] [main] INFO com.google.gerrit.sshd.SshDaemon : Started Gerrit SSHD-CORE-1.6.0 on *:29418
[2018-06-15 08:54:26,949] [main] INFO org.eclipse.jetty.server.Server : jetty-9.3.18.v20170406
[2018-06-15 08:54:28,040] [main] INFO com.googlesource.gerrit.plugins.gitiles.HttpModule : No /opt/gerrit/etc/gitiles.config; assuming defaults
[2018-06-15 08:54:28,847] [main] INFO org.eclipse.jetty.server.handler.ContextHandler : Started o.e.j.s.ServletContextHandler#62672ad5{/,null,AVAILABLE}
[2018-06-15 08:54:28,869] [main] INFO org.eclipse.jetty.server.AbstractConnector : Started ServerConnector#38503309{HTTP/1.1,[http/1.1]}{127.0.0.1:8081}
[2018-06-15 08:54:28,890] [main] INFO org.eclipse.jetty.server.Server : Started #20170ms
[2018-06-15 08:54:28,893] [main] INFO com.google.gerrit.pgm.Daemon : Gerrit Code Review 2.15.1 ready
[2018-06-15 08:54:44,819] [plugin-manager-preloader] INFO com.googlesource.gerrit.plugins.manager.OnStartStop : 45 plugins successfully pre-loaded
What have i missed?
Is it some permission settings that is wrong or configuration in gerrit.config that has to be done?
Directory gerrit/plugin has permissions set to: drwxr-xr-x
Note : I've tried restarting Gerrit.
Good to know: We are using nginx. That might be useful info.
I know very little about how nginx works.
What it looks like in the UI

Answer 1

The plugin-manager only works in the Old UI. If you're using the new PolyGerrit UI first click on "Switch to Old UI" link at the right/down on the page. Then the plugin-manager can be access at: Plugins > Manage menu.
If you're not able to see the "Manage" option in the Old UI check the following:
. Verify if you're logged in Gerrit with an Admin user (you need to have "Administrate Server" permission in All-Projects project). There're an specific permission to access Plugins > Installed item (called "View Plugins") but this permission doesn't work the same way to Plugins > Manage one.
. Verify if you have the following set in the GERRIT_SITE/etc/gerrit.config file:
[plugins]
allowRemoteAdmin = true
Maybe this can resolve your issue.