Since this is a new UI for you, I suggest that you follow the documentation on the steps, Vincent.
There is a step where you select the Update Manager image vs the Software AG Products image, which may seem confusing at first (I still get confused).
SUM usually updates itself first before letting you use it.
However, can you check the Update Manager logs in the background, to see if there’s a JVM update in progress? It should be under /<yourRootFolder>/SAGUpdateManager/logs unless you specified a different path.
KM
#Application-Platform#webMethods