Gradle plugin encounter 502 Bad Gateway when download gradle plugin from private Nexus Proxy Maven

I have this in in file 01-init-plugin-repo.gradle inside my gradle user home’s init.d folder

settingsEvaluated { settings ->
    settings.pluginManagement {
        repositories {
            maven {
                name "my-nexus3"
                url "https://mynexus/repository/maven-gradle-plugin/"
                //url "https://plugins.gradle.org/m2/"
            }

        }
    }
}

then this is my build.gradle

plugins {
  id "io.vertx.vertx-plugin"
}

And I have a Proxy repo setup in my Nexus directory, like this

But I am getting 502 bad gateway

org.gradle.internal.resolve.ModuleVersionResolveException: Could not resolve gradle.plugin.io.vertx:vertx-gradle-plugin:1.1.3.
Caused by: org.gradle.api.resources.ResourceException: Could not get resource 'https://mynexus/repository/maven-gradle-plugin/gradle/plugin/io/vertx/vertx-gradle-plugin/1.1.3/vertx-gradle-plugin-1.1.3.pom'.


      > Could not resolve gradle.plugin.io.vertx:vertx-gradle-plugin:1.1.3.
         > Could not get resource 'https://mynexus/repository/maven-gradle-plugin/gradle/plugin/io/vertx/vertx-gradle-plugin/1.1.3/vertx-gradle-plugin-1.1.3.pom'.
            > Could not HEAD 'https://mynexus/repository/maven-gradle-plugin/gradle/plugin/io/vertx/vertx-gradle-plugin/1.1.3/vertx-gradle-plugin-1.1.3.pom'. Received status code 502 from server: Bad Gateway

Is zit by default, gradle plugin will always try to resolve the plugin by append “gradle/plugin” to the path after the nexus repository url?
"https://mynexus/repository/maven-gradle-plugin/gradle/plugin/io/vertx/vertx-gradle-plugin/1.1.3/vertx-gradle-plugin-1.1.3.pom

I am using Gradle 6.X. What am I missing?

No, that’s just the artifact you try to resolve.
The way it works is this:
To translate a plugin id and version to a jar with the code, the conventional conversion to artifact is <plugin id>:<plugin id>.gradle.plugin:<version>, in your case io.vertx.vertx-plugin:io.vertx.vertx-plugin.gradle.plugin:1.1.3.
These marker artifacts for the id resolution usually don’t have a jar themselves, but just depend on the artifact with the actual plugin code, this way you can also easily have multiple plugins in one jar.
If you look at the POM of the mentioned coordinates: https://plugins.gradle.org/m2/io/vertx/vertx-plugin/io.vertx.vertx-plugin.gradle.plugin/1.1.3/io.vertx.vertx-plugin.gradle.plugin-1.1.3.pom
You see that there is a dependency on gradle.plugin.io.vertx:vertx-gradle-plugin:1.1.3 which then contains the actual plugin code. This is where the gradle/plugin/ comes from as it is part of the group of that artifact.