I run ganache, truffle and metmask. If I run the code below I get an error on the this.web3.eth.sendSignedTransaction() function:

        const tx_builder = this.contract.methods.createCountry("NL", 100, 100, 100000000, this.account);
        const encoded_tx = tx_builder.encodeABI();
        const transactionObject = {
            gas: 3000000,
            data: encoded_tx,
            value : 0,
            from: this.account,
            to: this.contractAddress
        };
        
        this.web3.eth.accounts.signTransaction(transactionObject, this.pvtKey)
        .then(signedTx => this.web3.eth.sendSignedTransaction(signedTx.rawTransaction))
        .then(receipt => console.log("Transaction receipt: ", receipt))
        .catch(err => console.error(err));

The error is the following: 

    index.js:2178 Error: Returned error: {"id":6,"jsonrpc":"2.0","error":{"code":-32603}}
    at Object.ErrorResponse (errors.js:29)

I have absolutely no idea where to look anymore and feel like I've tried everything, might it have anything to do with the fact that I'm connected to metamask?  When I try to send this transaction through metamask with eth.method.send() the transaction does not give an error and behaves as expected.