After installinging WP User Frontend my testsite broke down.
Received a message that there was no access to a line in a php file of the UAM plugin.
I had to remove WP User Frontend plugin after that my site works again.
I removed the UAM plugin and reinstalled WP User Frontend.
Now it works but that is no option for me, I want to use UAM.
What do I have to do to get it working.