Avrdude error when uploading

[EJ Salga]

I get this error:

avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x00

When I upload this code to my Nano:

#include <Servo.h>

Servo myservo;  
int potpin = A0;
int val;   

void setup() {
  myservo.attach(9); 
} 

void loop() {
  val = analogRead(potpin);        
  val = map(val, 0, 1023, 0, 180);    
  myservo.write(val);                  
delay(15);                          
}

The Arduino help center says I might have selected the wrong board and port. So I reselected the Nano board and put in COM3. I also reinstalled the CH340 driver as my Arduino is a clone. I’ve tried reuploading and restarting but nothing seems to work and I get the same error. 

Any help is much appreciated.