Despite this issue is better discovered using Fastpath, this issue is relative to the openfire projet where the org.jivesoftware.openfire.plugin.fastpath.workgroup_002dqueues_jsp is located.
Reason of moving this report from fastpath plugin to main openfire discussion.
DataForm dataForm = formManager.getDataForm(workgroup); returns null leading to NPE.
This happen for any workgroup, including default one after fastpath install, after any server shutdown, at least for the embeded database.
As previouly said, there is a workaround updating the form UI after each openfire restart, a bit boring anyway.
Didn’t succeed yet at running openfire in debug mode to get more information.