App Inventor 2 BLE, Sending and receiving strings


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: )
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.