Bosch SMI40E85 "check water supply" is blinking

Hi Guys, thanks for accepting me to the forum.

I had this light blinking on my machine. did the following:

1. checked water supply: OK

2. checked flow rate: OK

3. checked the filter: OK

4. checked the waste pump impeller for free movement: OK

5. checked the drain hose: OK

the light still blinks.

I took the power plug out again, took off the inlet hose (with the solenoid) from the faucet, and put it back up. I put the power plug back in, now the light went off.

This made me suspect that maybe the solenoid is on the edge...

Anyhow, I used the opportunity that the machine is out, to clean the water inlet assembly. took it off, cleaned it, and put it back in place, not forgetting to plug back in the flow-through sensor connector.

I connected the machine again, and again the light starts blinking. So now, I start thinking it could be the water level sensor.

So next thing I do, is I place the machine on its back, so I can investigate forward. After a bit of wondering, I understand that I'm stuck, not really knowing how to get to the water reservoir

So I decided to put everything back in place and search for further help. but just before I head up to post this, I try one more time, and now it's working again.

bottom line:

I'm pretty sure I'm running on fumes here... so any tips on how to deal with this, so I can prepare before it happens again, are appreciated

Thanks