GrovePi - Rotary Angle Sensor


im really new to Raspberry and GrovePi and i have problems which i cant solve. I have the Raspberry 3b and Grove Pi Plus.
So i want to use the rotary angle sensor to read the value of the rotary. I follow these instructions here: . But when i run the code for " Play With Raspberry Pi (With Grove Base Hat for Raspberry Pi)" i get this error:
Check whether I2C enabled and Grove Hat RPI or Grove Base Hat RPI Zero inserted.
I enabled I2C via raspi-config and also restarted he pi. Didnt help.

When i run the code for " Play With Raspberry Pi (with GrovePi_Plus)" it does nothing. No error message and the led doesnt light up.

I have no experience with python, so i cant program my own code. But maybe someone can help me out.