Possible cause: Device and remote control are not yet or no longer paired.
Teufel Soundbar Streaming / Teufel Sounddeck Streaming / Corestation.
Pair device with remote control (again) by holding the supplied remote control directly near the front LED of Teufel Soundbar/deck Streaming and perform the following:
Press remote buttons 1 and 4 simultaneously until the LED on the remote flashes three times. By doing this, you will connect the remote to the device. After that, the remote control should work as usual
Note: If the LED flashes 10 times in a row instead, the connection attempt was not successful. Make sure the soundbar/deck is turned on and perform the process again.
Ultima Active (first generation) / Concept E 450 Digital / Concept E Digital / BOOMSTER (2020) / BOOMSTER XL / Corestation / Corestation Compact.
For pairing, the side button on the remote control must be pressed for up to max. 30 seconds (usually 10s).