Juwi, this is a problem with Comfigurator 3.7.7 not ULT
In older Comfigurator, the module scan sometimes takes a littel longer to get a reply from a module and Comfigurator reported it as not found
In Comfigurator 3.7.7 if the scan reply u? is too slow it gives the message that you see and asks you to try again
If you repeat the scan it should see the UCM/HM
If you have the same problem can you send the Monitor IO