TypeCover doesn't work on Surface Pro 3, how can I fix it?

[Windows Central Question]

TypeCover doesn't work on surface pro 3

Hello

Since a few days the Type Cover no longer works on my Surface Pro 3 (Win8.1). Neither the keys nor the touchpad or the backlighting.

For testing I changed the Type Cover with a friend. Result: my Type Cover works on his Surface, but his Type Cover doesn't work on my Surface, means there is something wrong with my Surface.

I cleaned the interface and it looks good.

In the device manager I can see only a "HID Keyboard", which drivers seems to be up to date.

What can I try? Any ideas?

Thanks and greetings