Klang Soundbar MR3 no sound since last update

wiscel

I have had a Loewe Klang Soundbar MR3 for a week now, which is connected to my Philips 909 Oled via HDMI Earc. Everything worked fine until I installed the latest firmware update (MV086_A 0.15 B 0.48 TX 27 _D 2.42.01.17).
After the update, there is no TV sound coming from the soundbar, also no more sound from apps such as Prime, Youtube. The soundbar still detects a connection to the TV, the light lights up automatically and the bar sees there is a sound signal, but no sound comes through.

I also have no sound through Play Fi. Even when the speaker is on, it does not respond to the volume buttons, the bass is also on +3, I can't turn that back.

I have already done several factory resets, ran the update several times, and replaced cables. But there is no sound coming from the speaker.

I suspect the soundbar is stuck in mute mode. In the Play Fi app I also see the soundbar with a red line through the speaker. How can I disable the mute mode? (Of course I used the mute/unmute button and also changed the batteries in the remote control.)