5.0.3 CAS and CAS Management throws "org.pac4j.core.exception.TechnicalException: clients cannot be null"

[Phillip Davey]

I'm new to CAS and I'm trying to setup a configuration that is backed by LDAP for authentication (eventual to be joined by gauth 2-factor), and uses mariadb for JPA-service registry.  I can currently get successful authentication, but when I try to use the management app,  I get the following:

2017-03-27 15:56:44,871 ERROR [org.springframework.boot.web.support.ErrorPageFilter] - <Forwarding to error page from request [/callback] due to exception [clients cannot be null]>

org.pac4j.core.exception.TechnicalException: clients cannot be null

at org.pac4j.core.util.CommonHelper.assertTrue(CommonHelper.java:134) ~[pac4j-core-1.9.6.jar:?]

at org.pac4j.core.util.CommonHelper.assertNotNull(CommonHelper.java:155) ~[pac4j-core-1.9.6.jar:?]

at org.pac4j.core.engine.DefaultCallbackLogic.perform(DefaultCallbackLogic.java:67) ~[pac4j-core-1.9.6.jar:?]

at org.pac4j.springframework.web.CallbackController.callback(CallbackController.java:53) ~[spring-webmvc-pac4j-1.1.4.jar:?]

The url that is throwing it is:

https://galactica-prime:8443/singleSignOnCas/callback?client_name=CasClient&ticket=ST-2-jvO3drjwiUsYZSXFbLBm-galactica-prime

This occurs when I attempt to access the management app, even after previously authenticating with the main CAS app.  They are deployed on the same Tomcat. The app names (because of my IDE and maven config) are singleSignOnCas and singleSignOnMgmt.  I don't understand why pac4j is in the stack, since I've not got any authentication delegation configured that I'm aware of.

I'm sure I've just got some configuration wires crossed, but I'm not seeing much about this stuff out there.

As an aside, is 5.0.x current for production, or is the 4-series still mostly used?