Optimism Transaction Error

[jettblu]

Hello! I have encountered a tricky issue when making a simple transfer transaction on Optimism.

I use a standard UI flow to construct the following transaction object (output by Ethers.Js). The transaction specifies a simple transfer of the native token from one address to another.

chainId: 10

from: "0x0000000000000000000000000000000000000000"

gasLimit: BigNumber {_hex: '0x5208', _isBigNumber: true}

gasPrice: BigNumber {_hex: '0x0f4240', _isBigNumber: true}

nonce: 1

to: "0x0000000000000000000000000000000000000000"

type: 1

value: BigNumber {_hex: '0x02c3c2eead45f1', _isBigNumber: true}

Note: I have changed the addresses for privacy.

I then use the following code to serialize and sign the transaction:

        let signingKey:SigningKey = new SigningKey(newHDKey.privateKey);
        if(!SigningKey.isSigningKey(signingKey)){
            throw(new Error("Error: Unable to create EVM signing key from hd private key."))
        }
        let txResolved = await resolveProperties(transaction);
        if(txResolved.from != null) {
            if (txResolved.from.toLowerCase() !== account.address.toLowerCase()) {
                throw Error("transaction from address mismatch");
            }
            delete txResolved.from
        }
    
        const txDigest = keccak256(serialize(<UnsignedTransaction>txResolved))
        const sigObject = signingKey.signDigest(txDigest);
        txResolved.from = account.address
        const signedTx = serialize(<UnsignedTransaction>txResolved, sigObject);
        return signedTx;

However, when I publish the signed and serialized transaction, the Optimism RPC returns the following error: rlp: expected input list for types.txdata. The same flow works just fine for other networks including pre-EIP1559 Layer 2's like Arbitrum.

I have searched online for similar issues/solutions to no avail. Does anyone have an idea as to what may be causing this problem?