UNSOLVED MMM-MotionDetector image seems too dark

[breadward]

Hey Guys,
i’m basically done with my first mirror (hooray!). I put a lot of work in it and now one important thing doesnt seem to work.
I’m using the MMM-MotionDetector Module with a Rpi Cam to save some energy.
Well when i assembled the tech stuff without a mirror my system seemed to work as i wanted to.
Since i assembled it all together the Module doesnt seem to consider my images as relevant.
I used

raspistill -0 

to check if my camera isnt able to peek through the mirror.
Turns out that i see the other side but i’d consider it dark. You can still see everything on the image tho.

I turned off the red camera light, i thought this might dazzle the camera. But this doesnt help as well.

I already tried to config my threshold=1 but this doesnt seem to help as well.
When i use e.g. a flashlight and hold it right onto the camera the module gets a high score and the monitor is turning on again.

Do you have any idea how i could get it to work properly?

Sorry, this is my first post. If any Information is missing let me know.

Thanks in advance!
Kind regards from Germany.