Our Jenkins server was very out of date. I don't remember the previous version but after updating to 2.368 which seems to require Java 17 (server won't start with Java 11.0.2) the Active Directory plugin fails with (Active Directory plugin was updated to latest):

2022-09-15 21:01:00.271+0000 [id=493163] WARNING h.i.i.InstallUncaughtExceptionHandler#handleException: Caught unhandled exception with ID f5d3268f-6af3-40c4-bcbd-08bea4c7838acom4j.ComException: 8007203a The server is not operational. : The server is not operational. : .\invoke.cpp:517at com4j.Native.invoke(Native Method)at com4j.StandardComMethod.invoke(StandardComMethod.java:35)at com4j.Wrapper$InvocationThunk.call(Wrapper.java:356)at com4j.Task.invoke(Task.java:50)at com4j.ComThread.run0(ComThread.java:172)at com4j.ComThread.run(ComThread.java:153)Caused: com4j.ComException: 8007203a The server is not operational. : The server is not operational. : .\invoke.cpp:517at com4j.Wrapper.invoke(Wrapper.java:187)at jdk.proxy8/jdk.proxy8.$Proxy55.openDSObject(Unknown Source)at hudson.plugins.active_directory.ActiveDirectoryAuthenticationProvider.<init>(ActiveDirectoryAuthenticationProvider.java:150)at hudson.plugins.active_directory.ActiveDirectorySecurityRealm.createAuthenticationProvider(ActiveDirectorySecurityRealm.java:890)at hudson.plugins.active_directory.ActiveDirectorySecurityRealm.getAuthenticationProvider(ActiveDirectorySecurityRealm.java:882)at hudson.plugins.active_directory.ActiveDirectorySecurityRealm.loadUserByUsername(ActiveDirectorySecurityRealm.java:899)at hudson.security.AbstractPasswordBasedSecurityRealm.loadUserByUsername2(AbstractPasswordBasedSecurityRealm.java:118)at jenkins.security.UserDetailsCache$Retriever.call(UserDetailsCache.java:170)at jenkins.security.UserDetailsCache$Retriever.call(UserDetailsCache.java:159)at com.google.common.cache.LocalCache$LocalManualCache$1.load(LocalCache.java:4868)at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3533)at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2282)at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2159)at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2049)Caused: com.google.common.util.concurrent.UncheckedExecutionException

The Jenkins UI for Configuring global security contains the attached image at the bottom of the page.

It seems this plugin still requires Java 8 and won't work with newer versions which is a issue since Jenkins needs Java 17 or that is as much as I can determine why it would have stopped working.