Naja, in Ordnung denn.
Weill ich dasselbe Problem auf ein Englischsprachiges Forum geantwortet habe, bekommst Du das Antwort in English. Wenn das ein Problem ist, dann melde wieder zurück.
In Simatic Manager, expand the WinCC Flex HMI so much that you can see the Configuration of same in the right part of the screen. Open the Configuration ; this switches to HW Config.
In the HW Config, delete everything except the WinCC Flexible RT index.
(So you must delete IE General).
Select from the menu Station .. Properties. Select the Configuration tab. Make sure that S7RTM is deselected.
Save and compile.
Open the WinCC Flexible project.
Open the connection properties.
Recreate the connection by manually specifying to use S7ONLINE, Ethernet, specify the IP and Subnet of both PC and PLC, and rack=0, slot=2.
Save and compile.
You may get error messages that symbols cannot be connected. Just ignore.
Transfer the RT to the target PC.
Restart the RT