How can I reactivate my speaker?

The battery is probably deeply discharged. This will be a bit tricky. Try different chargers. Some with more and some with less power. Often specified in watts or something like that. Then you have to leave it on for several hours. I recommend at least 6 hours per charger. Then you can try switching it on.

Maybe someone knows about repairs. You could ask them if they can test/replace the battery.

Hi Jochen, thanks for the answer. Unfortunately it didn't work. The speaker is "alive" again, but only all the LEDs came on in a strange purple tone, something between white and red. Otherwise it still does not react.

So according to the operating instructions, this means that you have a notification, possibly in Teams

should look like the lower half of the image.
Otherwise there is also the LED for half full battery:




and for a pretty empty battery:



Also try to reset the device once and set it up again, it might have a connection to another device.
If the USB cable is still intact, connect it to a computer and check if it still works.

No, all the LEDs were purple, but now they are off again and have not come back on despite recharging. Since the speaker no longer mucks itself - even if it is connected via cable - unfortunately no reset is possible, at least not with the buttons "Accept" and "Hang up". Is there another possibility for the reset, any kind of hard reset?Thank you and LG Michael