Node Red - Bad gateway after moving to PI


Because I was new to home Assistant and node red, I installed everything in a virtual box image. And I was able to create my flows in Node Red

Now I have moved everything to a Raspberry Py. But of course I don’t want to restart with everything.
I’ve read that the \config folder had to be copied from the old virtual box to the \config folder on the PI. What I did.

But now Node Red shows always “Bad gateway”. I uninstalled Node Red several times + reboot.

What should I do to start with a “fresh” node red instance?
After that, I think I have to import the 'flows.json" file.