Error: invalid length, need 256 bits

[PBillingsby]

This error is caused by exporting an invalid private key.

The private key must be a 64 character hexadecimal string of alphanumeric characters. It should look similar to this 4c0883a69102937d6231471b5dbb6204fe5129617082799a28b024b2e34a5f33.

You can find instructions on how to retrieve your private key from MetaMask here: https://support.metamask.io/managing-my-wallet/secret-recovery-phrase-and-private-keys/how-to-export-an-accounts-private-key