Unplug the cable on both ends and re-plug in.
Thx for the tipp. But I already tried it without positive effect.
In fact I already tried various things:
0) Checked for dirt.
Here is a look into the connection of the remote:
https://photos.app.goo.gl/rKGo9KGxqV9WCWq68
And here in connection with the Kemper:
https://photos.app.goo.gl/qMWjTDqfshSSd4wL8
1) I swapped the cables. Had tested an official Kemper remote replacement cable and various other network cables. Without any effect. Besides one cable that worked (Kemper to PoE Hub, Remote to PoE Hub) and the other day it stopped working again. What is the status right now.
2) The remote receives power (green light) in the POE hub, but the data lamp (yellow light) does not flash. The Kemper's data lamp flashes.
See this video (black cable - remote, yellow cable - Kemper)
https://photos.app.goo.gl/VpwYAwf487oxmac3A
3) Connected directly to the Kemper, the Kemper light does not flash:
https://photos.app.goo.gl/B19KJQQiG54KmUaQ8
When I connect the Kemper to the POE hub, the lamp starts flashing immediately:
https://photos.app.goo.gl/Wxze3zC9LLoMytkz7
4) Kemper Remote to POE injector
See this video: https://photos.app.goo.gl/KAK3shmfiesr6JQp7
As soon as I connect the remote, the light on the POE injector goes out, which is not normal.
Are the two incompatible? Or does the remote create something like a short circuit?