New AXR4U and reamping guitar via Kemper Profiler Rack now leads to terrible feedback

Another problem:
I have been using a Kemper Profiler Rack for quite some time now to first record the direct electric guitar signal from Kemper to Cubase, then editing the clean signal in my project to be more or less in time, to finally put the edited signal on another audio track (with no inputs or outputs) and send it from CUE3 of the control room to the Kemper and record the reamped signal on a new audio track.

After installing the AXR4U, this is not possible anymore. I’m now going into MIC/LINE/Hi-Z input 2 to record the reamped signal to make use of the preamp’s silk texture. When I turn on the Kemper, I get a loud and terrible feedback. I already changed the cables but that’s not the problem. There isn’t even a signal going out from CUE3. Even when I mute the whole Cubase output, the feedback stays.

Right now I’m totally frustrated with this AXR4U and want to send it back. I expected it to work like a charm and make everything easier … but on the contrary.

How about a warning sticker on the packacking:
“Don’t buy this unit when you use Cubase Pro.”