I am using web3.js 1.0.36 to connect connect the blockchain. But unfortunately this code cannot connect to metamask, if it has been enabled.

var metamask = false;
if (typeof web3 !== 'undefined') {
    web3 = new Web3(web3.currentProvider);
    metamask = true; 
    web3.eth.defaultAccount = web3.eth.accounts[0];
} else {
    web3 = new Web3(new
    Web3.providers.HttpProvider(infuraUrl));
    var address = web3.eth.accounts.create().address;
}
myContract = new web3.eth.Contract(abi,contractAddress);
myContract.methods.Register((Name,Id).send({},function(error,result){
    if (! error)
        console.log(result);
    else
        console.log(error);
});

When we run this program with Metamsk it displays this error:

Error: Returned error: Error: MetaMask Tx Signature: User denied transaction signature.

but when I mention a fixed address it works:

myContract.methods.Register((Name,Id).send({from: '0x...'},function(error,result){
        if (! error)
            console.log(result);
        else
            console.log(error);
    });

For some reasons I can't bring the address itself in the source and I want it to get the address from Metamask. What should I do?