While on a clustered environment running wildfly 8.2.1 with mod_JK, when trying to View users, groups, organizations, etc. you receive the following error
1) This error is displayed on the UI due to the version of mod_JK that is being used.
2) Configuration errors inside workers.properties/standalone.bat files.
1) please upgrade the version of mod_JK you are using. If the version is out dated this will cause the error displayed above. A working version of mod_JK that works with wildfly 8.2.1 is 1.2.40.
2) Update the worker.worker1 to match the node_name on the standalone.bat file.
On the standalone.bat file it will say "set "NODE_NAME=iamnode0"" copy the node_name and replace worker1 with the node name to look like worker.iamnode0.
Afterwards restarts the clustered environment and the issue should no longer be present.