Bluetooth connection with multiple screens app inventor

I've design an app for android using app inventor, to send commands so that an Arduino microcontroller decode this commands. I've been watching tutorials all over youtube and I have manage to connect to a Bluetooth module HC-6. 

The problem is that I couldn't stay connected with the bluetooth module with the others screen, which consists of clicking the buttons to send the commands. Then I use the block "open another screen, start value" to send a variable that contain the  MAC Address of the android device. But after watching and reading a lot, I couldn't find an answer about why i cannot stay connected after changing screens in the app. In other words, In the main screen I can send data but when i try to send data from another another then the erro of loose connection appears. 

The error that shows up when the connection is lost is "Error 507" of app inventor.

PS: sorry about my English, is pretty lame.

for bluetooth I recommend you to use only one screen

to simulate different screens, just use vertical screen arrangements and set them to visible = false or true as needed

Thanks for your response!