Flip to shush does not work anymore

I noticed that after flipping my phone I was still getting notifications that otherwise wouldn't have gone through. I looked at the setting and turned it off but now it gives me an error message and won't turn on again. I have tried restarting it, turning it off for a long time and searching for updates. But nothing worked. It also seems that no one else has had in recent times. I hope that someone has a solution or any other ideas.

Thanks in advance