Please check the groups remarks on issues during calibration.
My first idea was to check the power supplied on the potmeter, middle pin goes to A7 I think. Higher voltage >5Volt may have ruined your port, and maybe still applying this voltage prevents the Arduino from booting or even accepting a reprogram. First attempt
beside measuring the voltages applied is to disconnect A7 wire for now.
The red wire is indeed the correct one.
The repeated issues on calibration is a concern due to repeated issues reported.
