php 2 if statements help

Hi, i wrote this code, basically i want users to only be able to create 1 crew, but for some reason it's not working, any help is appreciated.

elseif($username == $checkifleaderofcrew){

echo("You already have a crew");
}

This part isn't working.

 <?php
	if(isset($_POST['crew'])){
		
		$username = $_SESSION['username'];
		
		$crewname = mysqli_real_escape_string($con, $_POST['crewname']);
		$crewname1 = preg_replace('~[^a-zA-Z0-9]+~', ' ', $crewname);
		
		$query = mysqli_query($con, "SELECT * FROM crews WHERE name='$crewname1'");
		while($row = mysqli_fetch_array($query))
 		{
 	    $checkcrewname = $row['name'];
		$checkifleaderofcrew = $row['username'];
  		}	
		$hascrew = mysqli_query($con, "SELECT * FROM crews WHERE username='$username'");
		
	    if($checkcrewname == $crewname1){
        echo("Crew name taken");
		}
        elseif($username == $checkifleaderofcrew){
        echo("You already have a crew");
        } 
		else{
		$thequery = mysqli_query ($con, "INSERT INTO crews (name, username, members, wins, losses)
        VALUES ('{$crewname1}', '{$username}', '1', '0', '0')");	
		mysqli_real_escape_string($con, $thequery);
		echo "Crew has been successfully created";		
		}
	}
	
	?>