Blutooth module HC 05 to upload code NOT working

I've been trying to upload code on arduino using Bluetooth module HC-05 according to this link:

but it's not working. in the last step; uploading the code.

although, the AT mode runs and responds 'OK' successfully.

I've made sure of the circuit connections multiple times. it says "uploading" for a long time but then it returns this error:
"avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x04
avrdude: stk500_recv(): programmer is not responding"

and continues on for the rest of the ten trials.

has anyone faced this before or knows what could be wrong?