Ganache Error – Invalid JSON RPC Response: “” in Ganache

let send_add = send_public_address;

let recv_add = rec_public_address;

let transfer_amount = web3.toWei(data.amount, 'ether');

let nonce = web3.toHex(web3.eth.getTransactionCount(send_public_address));

var private_key = privatekey_sender.slice(2);

let gas = web3.toHex(data.gas_limit);

let gasPrice = web3.toHex(data.gas_price);

var rawTx = {

        from: send_add,

        nonce: nonce,

        gasLimit: gas,

        gasPrice: gasPrice,

        value: web3.toHex(transfer_amount),

        to: recv_add,

    };

var transaction = new tx(rawTx);

var txData = new Buffer(private_key, 'hex');

transaction.sign(txData);

var serializedTx = transaction.serialize().toString('hex');

web3.eth.sendRawTransaction('0x' + serializedTx, function (err, txHash) {

  if (txHash) {

            next(null, txHash);

        }

        else if (err && err.message) {

            next(err.message, null);

        }

        else {

            next('Unable to sendRawTransaction', null);

        }

    });

You need to make geth listen on the IP address from which your server can be reached externally:

admin.startRPC(<external ip address>, 8545, "*", "web3,db,net,eth")

If you specify the localhost, geth accepts only local connections, i. e. connections that come from the same machine, but not from remote.