cant uplad any sketch and the "l led" is always on

Hello everyone

when i try to connect my Nano v3.0( ) to my pc , the l led is always on and i cant upload a sketch.

every time i try to upload a sketch i get this error:
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x08
but the 0x08 at the end is always different.

i tried the loopback test but i got nothing echoed back.
the right port is selected.
im using Windows 10 and my IDE version is 1.8.13

Any assistance will be appreciated.