Unexpected end of input error in react native - reactjs

Question

I get an error prompt SyntaxError: Unexpected end of input when I try to the message from API.
Here is my code:
.then((response) =>response.json())
.then((response)=>{
alert(response[0].Message);
})
.catch((error) => {
alert("Error"+error);
});
If I change to the code below, it runs well with no errors, but it will not prompt any successful message.
try{
((response) =>response.json()),
((response)=>{
alert(response[0].Message);
})
}
catch{
((error) => {
alert("Error"+error);
})
}
Here is the api script:
<?php
$CN = mysqli_connect('localhost', 'root', '');
$DB = mysqli_select_db($CN, 'iostest');
$EncodedData = file_get_contents('php://input');
$DecodedData = json_decode($EncodedData, true);
$userid = $DecodedData['userid'];
$jid=$DecodedData['jid'];
$job=$DecodedData['job'];
$mcode=$DecodedData['mcode'];
$insertuserid = "insert into scan(user,job,jobid,machinecode) values ('$userid','$job','$jid','$mcode')";
$register = mysqli_query($CN, $insertuserid);
if ($register)
$Message = "Member has been registered successfully";
else
$Message = "Server Error... please try latter";
$Response[] = array("Message" => $Message);
echo json_encode($Response);
?>