Gradle cannot access a plugin JAR, gets a 500 status code

I am seeing this error for the first time. Up until this invocation, Gradle has had no problems getting this plugin JAR:

Error resolving plugin [id: ‘net.ossindex.audit’, version: ‘0.3.8-beta’]

Could not resolve all dependencies for configuration ‘detachedConfiguration1’.
Could not determine artifacts for net.ossindex.audit:net.ossindex.audit.gradle.plugin:0.3.8-beta
Could not get resource ‘’.
Could not HEAD ‘’. Received status code 500 from server:

If I go to, I get the message

  "errors" : [ {
"status" : 404,
"message" : "Could not find resource"
  } ]

I must be missing something. Was this file removed, or perhaps the 500 status indicates some other error?

The relevant script code is

buildscript {
  repositories {
    maven {
      url ""
  dependencies {
    classpath ""

apply plugin: "net.ossindex.audit"