Why ? Error 507, unable to connect. is this device turned on? help

MIT App Inventor Help
1

I tried to program it like this to drive the DC motor, but it didn't work.

dd
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If you run Error 507, you cannot connect to connect. is this device turned on? The message appears.
I'm using an Android phone and have confirmed that Bluetooth and location services are all turned on.
We need your help.I am using a Galaxy S10. BT : HM-10

2

Please have a search in the community for Error 507, you may find clue or you would be able to conclude.