App Inventor 2 BLE, Sending and receiving strings

Hi,

I am trying to read strings from my Arduino, I am sending sensor values as strings.
I have followed the tutorials and everything was so for so good until I could not read strings.
I think the problem is at service UUID and char. UUID, the functions provided in stringsReceived did not work for me and I did the following (still not working :frowning: )
Unbenannt
Do you have any suggestions?
Thanks in advance.

Please see the examples at Multiple Bluetooth connection in one screen

Though you only have one connection, the ideas are the same.