PHP - Ipn Fsocketopen Failure

I am working on an e banking web app. So i was stuck on the transferring to the same bank page.. I have spent a lot of time to check where the errors are to no avail. The issue is the code doesnt work it gives a blank page...

    This is 12.php for the post action

<?php
session_start();
        error_reporting(E_ALL);
        
ini_set('display_errors', TRUE);

  if(!isset($_SESSION['login']))
    {
     header('Location: ../clogin.php');
      }

f (isset($_POST['transfer'])) 

      {

    $db['db_host'] = "localhost";
$db['db_user'] = "***"";
$db['db_pass'] = "***";
$db['db_name'] = "***";

foreach($db as $key => $value){
define(strtoupper($key), $value);
}

$connection = mysqli_connect(DB_HOST, DB_USER,DB_PASS,DB_NAME);

$query = "SET NAMES utf8";
mysqli_query($connection,$query);

if(!$connection) {
    echo "database not connected";
}
//get info
 /  $sql = "select firstname,lastname, middlename,username,balance from customer where username = '".$_SESSION['login']."'"; 

send query
/$sql2 = mysqli_query($connection, $sql);

//check query 
if(!$sql2)
{ 
die('ERROR:' . mysqli_error($connection)); 
}
//get trans details
$firstname =  $_POST['firstname'];

              $lastname  =  $_POST['lastname'];   
                   $middlename  =  $_POST['middlename'];          
              $account_number  =  $_POST['accountNumber'];
              $transAmount = $_POST['transAmount'];
              
 $description = $_POST['description'];
 
 $otp =$_POST['otp'];
 
              
$sql3 = "select firstname, lastname, middlename, account_number,balance,otp,otpTime,transLimit from customer
                        where account_number = '$account_number'  ";
               $result3 = mysqli_query($connection,$sql3);

if(!$result3) {
        die('ERROR:' . mysqli_error($connection));
    }

                       
while($row3 = mysqli_fetch_assoc($result3))
{
    
              $rfirstname  = $row3['firstname'];
                             $rlastname   = $row3['lastname'];  
                             $rmiddlename = $row3['middlename'];
                             $raccountNumber = $row3['account_number'];
                  

if($rfirstname !== $firstname &&  $rlastname !== $lastname &&    $rmiddlename !== $middlename && $raccountNumber !== $account_number)           
                         { 

echo'<script>swal.fire("FAILED!!", " The Account Number doesnt match the Account Name. Check Well", "error");</script>';
}

else if($rfirstname == $firstname &&  $rlastname == $lastname &&    $rmiddlename == $middlename && $raccountNumber == $account_number)
 
                            
{
    
    $totalTrans = $transAmount + 30;
    
$sql5 = "SELECT * FROM customer WHERE username = {$username}";
$result5 = mysqli_query($connection, $sql5);
    
    //check query
    if(!$result5) {
        die('ERROR:' . mysqli_error($connection));
    }
    
while($row5 = mysqli_fetch_assoc($result5))
{
$balance = $row5['balance'];

if($totalTrans > $row5['balance'])
{
    echo'<script>swal.fire("FAILED!!", " Insufficient Funds", "error");</script>';

}

}//while balance
    
 $sql6 = "SELECT * FROM customer WHERE username = {$username}";
$result6 = mysqli_query($connection, $sql6);
    
    //check query
    if(!$result6) {
        die('ERROR:' . mysqli_error($connection));
    }
    
while($row6 = mysqli_fetch_assoc($result6))
{  

$transLimit = $row6['transLimit'];

$acctype = $row6['acctype'];

if($transAmount > $row6['transLimit'] && $row6['acctype'] == 'savings')
{
    echo'<script>swal.fire("FAILED!!", " You can Only transfer maximum of 500,000 naira per time", "error");</script>';
}
if($transAmount > $row6['transLimit'] && $row6['acctype'] == 'current')
{
    echo'<script>swal.fire("FAILED!!", " You can Only transfer maximum of 5,000,000 naira per time", "error");</script>';
}

}// end of while transLimit

$sqla = "SELECT * FROM customer WHERE username = '".$SESSION['login']."'";
           
  $sqla = mysqli_query($connection, $sqla);  
    
    
if(!$sqla) {
        die('ERROR:' . mysqli_error($connection));
    }
  while($rowa = mysqli_fetch_assoc($sqla))
  {  
 $otp = $rowa['otp'];
 $db_username = $rowa['username'];
           $db_email = $rowa['email'];
           $otpTime = $rowa['otpTime'];
           $time_now = strtotime($otpTime);
           
     

if($otp !== $rowa['otp'])
{
    echo'<script>swal.fire("FAILED!!", " OTP does not match", "error");</script>';
}
if($otp == $rowa['otp'] && (time() - $time_now > 3 * 60))
{
echo'<script>swal.fire("FAILED!!", " OTP expired. Press Resend", "error");</script>';
}
 $sqlb = "update accounts set otp = null where username = '".$_SESSION['login']."' ";     
  
$resultb = mysqli_query($connection, $sqlb);
    
    //check query
    if(!$resultb) {
        die('ERROR:' . mysqli_error($connection));
    }
  
}// while end

$sqlc = "SELECT * FROM customer WHERE username = {$username}";
$resultc = mysqli_query($connection, $sqlc);
    
    //check query
    if(!$resultc) {
        die('ERROR:' . mysqli_error($connection));
    }
    
while($rowc = mysqli_fetch_assoc($result5))
{

$transLimit = $rowc['transLimit'];
$otp = $rowc['otp'];
$balance = $rowc['balance'];
$otpTime = $rowc['otpTime'];

$time_now = strtotime($otpTime);
$totalTrans = $transAmount + 30;

if($rfirstname == $firstname &&  $rlastname == $lastname &&    $rmiddlename == $middlename && $raccountNumber == $account_number && $totalTrans < $transLimit && $totalTrans <= $row['balance']  && $otp == $row['otp'] && (time() - $time_now < 3 * 60))
{
    $sql9 = "update customer set balance = $balance - $totalTrans
                          where username = '".$_SESSION['login']."'";
                
$result9 = mysqli_query($connection, $sql9);
    
    //check query
    if(!$result9) {
        die('ERROR:' . mysqli_error($connection));
    }
  

  $sql10 = "update customer set   balance = $balance + $transAmount
                          where firstname = '$rfirstname' and lastname= '$rlastname' and account_number = '$raccountNumber' and middlename= '$rmiddlename' ";
$result10 = mysqli_query($connection, $sql10);
    
    //check query
    if(!$result10) {
        die('ERROR:' . mysqli_error($connection));
    }
                 
                 
                 
                 
}//end of if
}//end of while

$sqlf = "SELECT * FROM customer WHERE username = {$username}";
$resultf = mysqli_query($connection, $sqlf);
    
    //check query
    if(!$resultf) {
        die('ERROR:' . mysqli_error($connection));
    }
    
while($rowf = mysqli_fetch_assoc($result5))
{

$db_username = $rowf['username'];
$db_email = $rowf['email'];

$msg = " <!DOCTYPE html><body>Dear <h1> $db_username, </h1>
 <h2><font color='darkviolet'>You transferred $transAmount to $rfirstname $rlastname $rmiddlename  with account Number $raccountNumber . Transaction statement/history is available on your portal for reference purposes.Thanks For banking with Us<b>.
 <br> If you didnt request for this transaction, contact your bank immediately!!!</font></h2>.....<br></b><i><font color='blue'>MMFB</font></i>
  </body></html>

$headers = "";
$headers .= "From: Mayor Microfinance Bank(MMFB)<admin@mmfb.com.ng> \r\n";
$headers .= "Reply-To:" . $db_username. "\r\n" ."X-Mailer: PHP/" . phpversion();
$headers .= 'MIME-Version: 1.0' . "\r\n";
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n"; 
$send = mail("$db_email","SUCCESFUL TRANSACTION",$msg,$headers);
}//end of while

$transid = substr(str_shuffle('abcdefghijklMnopqrstuvwxyz01234567890') , 0 , 10 );

$status1 = '<button class="button">CREDIT</button>';

$status2 = '<button class="button2">DEDIT</button>';

$sqlm = "SELECT * FROM customer WHERE username = {$username}";
$resultm = mysqli_query($connection, $sqlm);
    
    //check query
    if(!$resultm) {
        die('ERROR:' . mysqli_error($connection));
    }
    
while($rowm = mysqli_fetch_assoc($resultm))
{
$sfirstname = $rowm['firstname'];
$smiddlename = $rowm['middlename'];
$slastname = $rowm['lastname'];
$date = date("d/m/Y");

$sql11 = "insert into transactions where account_number = '$raccountNumber'
                                 (status,firstname,lastname,middlename,transAmount,date,account_number,description,transid,type)
                                   values  
                                  ('credit transaction',$sfirstname', '$slastname',
                                   '$smiddlename',
                                   '$transAmount', '$date',
                                   '$raccountNumber',
                                   '$description', '$transid', '$status1')";

                     //   $result11 = $connection->query($sql11);
                        $result11 = mysqli_query($connection, $sql11);
    
    //check query
    if(!$result11) {
        die('ERROR:' . mysqli_error($connection));
    }

$sql12 = "insert into transactions where username = '$username'
                                 (status,firstname,lastname,middlename,transAmount,date,accountNumber,description,transid,type)
                                   values  
                                  ('debit transaction','$firstname', '$lastname',
                                   '$middlename',
                                   '$transAmount', '$date',
                                   '$accountNumber',
                                   '$description', '$tranid', '$status2')";

$result12 = mysqli_query($connection, $sql12);
    
    //check query
    if(!$result12) {
        die('ERROR:' . mysqli_error($connection));
    }

}//end of ehile
$sql15 = "SELECT * FROM customer WHERE username = {$username}";
$result15 = mysqli_query($connection, $sqlf);
    
    //check query
    if(!$result15) {
        die('ERROR:' . mysqli_error($connection));
    }
    
while($row15 = mysqli_fetch_assoc($result15))
{

$firstname = $row15['firstname'];
$lastname = $row15['lastname'];
$db_email = $row15['email'];

$sql16 = "SELECT * FROM customer WHERE account_numberr = $raccountNumber ";
$result16 = mysqli_query($connection, $sql16);
    
    //check query
    if(!$result16) {
        die('ERROR:' . mysqli_error($connection));
    }
    
while($row16 = mysqli_fetch_assoc($result16))
{
$remail = $row16['email'];

$msg = " <!DOCTYPE html><body>Dear <h1> $rfirstname $rlastname $rmiddlename </h1>
 <h2><font color='darkviolet'>Your account $raccountNumber has been credited with $transAmount from $firstname $lastname . Transaction statement/history is available on your portal for reference purposes.Thanks For banking with Us<b>.
 <br> If you didnt request for this transaction, contact ur bank immediately!!!</font></h2>.....<br></b><i><font color='blue'>MMFB</font></i>
  </body></html>

$headers = "";
$headers .= "From: Mayor Microfinance Bank(MMFB)<admin@mmfb.com.ng> \r\n";
$headers .= "Reply-To:" . $db_username. "\r\n" ."X-Mailer: PHP/" . phpversion();
$headers .= 'MIME-Version: 1.0' . "\r\n";
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n"; 
$send = mail("$remail","SUCCESFUL TRANSACTION",$msg,$headers);   

}//end while 1
}//end while 2

}

else 
{
    echo'<script>swal.fire("FAILED!!", " Something Went Wrong Try Again Later.", "error");</script>';
}

}//while 
}//submit

?>

Then my html form in transfer.php is

                       <form method="POST" class="form-horizontal mt-4" action="">

                                <div class="form-group">
                                    <label>Account Number</label>
                                    <input type="number" class="form-control" id="number" name="accountNumber" placeholder="Enter destination account No" required>
                                </div>

                                <div class="form-group">
                                    <label>Firstname</label>
                                    <input type="text" class="form-control" id="firstname" name="firstname" placeholder="Enter destination surname" required>
                                </div>

                                <div class="form-group">
                                          <label>Lastname</label>
                                    <input type="text" class="form-control" id="lastname" name="lastname" placeholder="Enter destination last name" required>
                                </div>

<div class="form-group">
                                          <label>Middlename</label>
                                    <input type="text" class="form-control" id="middlename" name="middlename" placeholder="Enter destination Middlename" required>
                                </div>
                                <div class="form-group">
                                          <label>Description</label>
                                    <input type="text" class="form-control" id="description" name="description"  placeholder="Enter transfer description" required>
                                </div>
                                <div class="form-group">
                                          <label>Amount</label>
                                    <input type="number" class="form-control" id="amount" name="transAmount" placeholder="Enter the amount to Send" required>
                                </div>
   <div class="form-group">      
<label>ENTER OTP<label>
        <input type="number" class="form-control" name="otp" placeholder="OTP" pattern="[0-9]{4}" title="Only Digits (4 digit required)" required>
          
</div>

<div class="form-group row">
                                  <div class="col-12 text-right">
                                        <button class="btn btn-primary w-md waves-effect waves-light" type="submit" name="transfer">Transfer</button>
                                    </div>
                                </div>

                                <div class="form-group mt-2 mb-0 row">
                                    <div class="col-12 mt-4">
                                        <p class="mb-0">You will be charged 30 Naira for Transfer fee.<a href="dash.php" class="text-primary"> No!! Cancel Transfer</a></p>
                                    </div>
                                </div>

                            </form>
<!-- <button type="button" id ="box" class="btn btn-primary w-md waves-effect waves-light">SEND OTP</button>  -->
                        </div>
                    </div>

                </div>

I will be glad if u can help me. Thanks in advance