Station: CRC error & invalid stuff bit

Hello everyone,

I am a beginner in this area, but I enjoy it a lot, so I would like to ask you for advice on where the mistake could be.
I have an AIS antenna in the apartment in front of the window (3rd floor) until this morning, which received signals.
Now I have attached the antenna outside and the Raspberry inside. Since then I have received almost no valid signals, only "CRC error" and "invalid stuff bit".
A few more words: the actual reception area is behind the house. So I think the outdoor location is better. Because the signals don't go through walls anyway, right? Unfortunately I don't have any other option.
I also have a (actually high-quality) window bushing. But with a direct connection to the antenna, it doesn't feel much better.

My questions: where can the error lie? Rather at the location or at the cables? The tilt of the antenna shouldn't matter, right?

I use a Raspberry Pi with dAISy HAT and OpenCPN.

I sketched the situation. I hope I have conveyed the information briefly and to the point.

Best regards

(Blue is the water.)