I have a "error 515 not connected to a bluetooth device"

Hello,

I have an issue with my HC-05 Bluetooth module. The goal of my project is to control my robot using the MIT App Inventor application. So, I bought an Arduino Mega board with a Mega Sensor Shields 2.0 and a Bluetooth module. I've installed everything, but when I try to connect with the application, it gives me an error 515 and refuses to connect (while it connects fine with another app). Do you know how to fix this? Thanks in advance.

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