Make sure you are copying your PRIVATE KEY and not your PUBLIC KEY.
If you are using metamask, you can get your PRIVATE KEY from
the 3 dots menu beside your public key,
and then account details
then export private key
Make sure you are copying your PRIVATE KEY and not your PUBLIC KEY.
If you are using metamask, you can get your PRIVATE KEY from
the 3 dots menu beside your public key,
and then account details
then export private key