unloading to uno

I can get my code verified no probs but on uploading I get the message
avidude stk500_get sync() not in sync resp+0x6b.

The frustrating thing about this is initially it uploaded no probs, but I want to test a servo and when I upload the program the above error message is given.

please help

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Remove any connections to pins 0 and 1 on your Arduino board. These pins are used for communication with your computer, including uploads. Connecting anything to these pins can interfere with uploads.

Make sure you have the correct board selected from the Tools > Board menu.

Make sure you have selected the port of your Arduino board from the Tools > Port menu.

Sometimes the port will be labeled with the board name in the menu. Other times it will not. If you don’t know which port is your Arduino board, you can find it like this:

  • Unplug your Arduino board from the computer.
  • Tools > Port
  • Note the ports, if any, listed in the menu.
  • Close the Tools menu. The ports list is only updated when the Tools menu is re-opened, so this step is essential.
  • Plug your Arduino board into the computer.
  • Tools > Port - The new port listed in the menu is your Arduino board.