I have a conundrum?

I have a Samsung Galaxy Tab Active 2 running Android 7 and it has MobiControl client 13.5.1.1044. It has a lockdown screen and MobiControl is one of the apps available.  All other apps open as expected but MobiControl does not.  The screen just flashes and returns to the lockdown screen.  This has only happened to one device but cynical experience says it could become an issue.

I have other Tab 2s on this and other clients running fine.  Also Tab 1s again with no issue.

The link on lockdown HTML is launch://net.soti.mobicontrol.elm.samsung.  If I disable the lockdown screen and open the client it opens fine.

Server is 14.1.4.1693 running in the cloud.

I'm open to suggestions