Error 507, unable to connect

Hi Utakarsha

Attached is an Enhanced Project that works with the actual Arduino Hardware + Sketch that I have already posted, AppToArduino_Cmds.txt.

As I mentioned before, keep the spoken commands short for best possible success with speech-to-text. In my code, when the User speaks, the result is compared to a list of the available commands - if found, the command is sent, if not found, the User is asked to try again.

BT_Basic_Setup_Send_Cmds.aia (9.9 KB)

Click on the Blocks image to see it full-size.
The voice command method I show here has been proven to work, used to drive a robot.

Another Youtube video, this video contains the code this topic refers to.
Voice Controlled Home Automation Using Arduino & Bluetooth Module | Android App on MIT APP Inventor

A few things wrong in the App Code of that Video, I would discourage people from trying to reproduce it.

Edit:
The Speech Recognizer Blocks are not used correctly, nor is the speech recognition itself - for example, whatever the User says is simply sent to the device without checking it's validity.

See my posts above for an example Application and matching Arduino Sketch that have been proven to work.