Error 801 MIT App Inventor

While creating sound recorder, I encountered error 801 which does not allow recording any sound:
"ERROR 801: An unexpected error occured while recording sound".
I rebuilt the application and looked for a YouTube video about this error but nothing is said about it anywhere.

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Error 801: An unexpected error occurred while recording sound

Check your phone settings for obvious things like is the microphone switched on. If you have another phone available, try that to eliminate the possibility that your first phone has a fault of some kind.

and read this: