I'm trying to create a multi user login system but when I try to log on it stays on the login page and doesn't move to the next page. What can I do?

index.php

<form method="post" class="form-horizontal">

<div class="form-group">
    <label class="col-sm-3 control-label">Email</label>
    <div class="col-sm-6">
        <input type="text" name="txt_email" class="form-control" placeholder="enter email" />
    </div>
</div>

<div class="form-group">
    <label class="col-sm-3 control-label">Password</label>
    <div class="col-sm-6">
        <input type="password" name="txt_password" class="form-control" placeholder="enter password" />
    </div>
</div>

<div class="form-group">
    <label class="col-sm-3 control-label">Select Type</label>
    <div class=col-sm-3>
        <select class="form-control" name="txt_role">
            <option value="" selected="selected"> - Which one are you </option>
            <option value="admin"> Admin </option>
            <option value="parent"> Parent </option>
            <option value="swimmer"> Swimmer </option>
        </select>
    </div>
</div>

<div class="form-group">
    <div class="col-sm-offset-3 col-sm-9 m-t-15">
        <input type="submit" name="btn_login" class="btn btn-success" value="Login">
    </div>
</div>

<div class="form-group">
    <div class="col-sm-offset col-sm-9 m-t-15">
        You don't have an account at Water Tower 2000 <a href="register.php">
            <p class="text-info">Register Water Tower 2000 Account </p>
        </a>
    </div>
</div>
</form>

index.php PHP Code

<?php
require_once 'connection.php';
session_start ();

if(isset ($_SESSION["admin_login"]))

{
    header ("location:admin/admin_home.php");
}

if(isset ($_SESSION["parent_login"]))

{
    header ("location:parent/parent_home.php");
}

if(isset ($_SESSION["swimmer_login"]))
{
    header ("location:swimmer/swimmer_home.php");
}


if (isset ($_GET['btn_login'])) {

$email = $_GET ["txt_email"];

$password = $_GET ["txt_password"];

$email = $_GET ["txt_role"];

if(empty($email)){

$errorMsg[]="please enter your water tower email";

}

else if(empty($password)){

$errorMsg[]="please enter yout water tower email";
}

else if(empty($role)){

$errorMsg[]="please enter yout water tower email";

}


else if($email AND $password AND $role){

try{

$select_stmt=$db->prepare("SELECT email,password,role FROM masterlogin WHERE email=:uemail

AND password=:upassword AND role=:urole");

$select_stmt->bindParam(":uemail",$email);

$select_stmt->bindParam(":upassword",$password);

$select_stmt->bindParam(":urole",$role);

$select_stmt->excute();

while ($row=$select_stmt->fetch(PDO::FETCH_ASSOC)){

$dbemail =$row["email"];

$dbpassword =$row["password"];

$dbrole =$row["role"];

}
if($email!=null AND $password!=null AND $role!=null){

if($select_stmt->rowCount()>0){

if ($email!==$dbemail AND $password==$dbpassword AND $role==$dbrole){

switch($dbrole) {

case "admin":

$_SESSION ["admin_login"]=$email;
$loginMsg="Admin...Your in Water Tower...";
header("refresh:3;admin/admin_home.php");
break;

case "parent":
$_SESSION["parent_login"]=$email;
$loginMsg="Parent...Welcome To Water Tower...";
header("refresh:3;parent/parent_home.php");
break;

case "swimmer":
$_SESSION ["swimmer_login"]=$email;
$loginMsg="Fellow swimmer...Your in Water Tower...";
header("refresh:3;swimmer/swimmer_home.php");
break;

default:
$errorMsg[]="Sorry but either the email/password/role is wrong";
}

}



else {

$errorMsg="Sorry but either the email/password/role is wrong";
}

}

else {

$errorMsg="Sorry but either the email/password/role is wrong";

}

}

else{

$errorMsg="Sorry but either the email/password/role is wrong";

}

}



catch (PDOException $e){

$e->getMassage();

}

}

else {

$errorMsg="Sorry but either the email/password/role is wrong";

}

}

?>

<form method ="post" class="form-horizontal">

<div class ="form-group">
<label class = "col-sm-3 control-label">Username</label>  

<div class = "col-sm-6">  

<input type = "text" name="txt_username" class="form-control" placeholder = "enter username" />
</div>
</div>

<div class ="form-group">
<label class = "col-sm-3 control-label">Password</label>  

<div class = "col-sm-6">  

<input type = "password" name="txt_password" class="form-control" placeholder = "enter password" />
</div>
</div>

<div class ="form-group">
<label class = "col-sm-3 control-label">Username</label>  

<div class = "col-sm-6">
<select class = "" name="txt_role">
<option value = "" selected = "selected"> - select role - </option>
<option value = "swimmer">Swimmer</option>         

<option value = "parent">Parent</option>
</select>   

</div>
</div>

<div class = "form-group">
<div class = "col-sm-offset-3 col-sm-9- m-t-15">    

<input type = "submit" name="btn_register" class="btn btn-primary" value = "Register">
</div>
</div>

<div class = "form-group">
<div class ="col-sm-offset-3 col-sm-9 m-t-15">
You have an account at Water Tower? <a href = "index.php"><p class = "text-info">Login Account </p></a>        

</div>
</div>

</form>

<?php

require_once 'connection.php';

if(isset ($_GET["btn_register"])) 

{

if (isset ($_GET['btn_login'])) {
    $username = $_GET ["txt_username"];
    $email = $_GET ["txt_email"];
    $password = $_GET ["txt_password"];
    $role = $_GET ["txt_role"]


if(empty($username)){
    $errorMsg[]="please enter your usernmae";
}

else if(empty($email)){
    $errorMsg[]="please enter your email";
}

else if(!filter_var($email,FILTER_VALIDATE_EMAIL)){
    $errorMsg[]="please enter a valid email address ";
}

else if(empty($password)){
    $errorMsg[]="please enter password";
}    

else if (strlen ($password) < 6) {
    $errorMsg[]="It needs to be more than 6 characters";
}

else if (empty($role)) < 6) {
    $errorMsg[]="Please select a role";
}


try{
$select_stmt=$db->prepare("SELECT username,email FROM masterlogin WHERE username=:uname OR
email=:uemail");

$select_stmt->bindParam(":uname",$username);
$select_stmt->bindParam(":uemail",$email);
$select_stmt->excute();
$row=$select_stmt->fetch(PDO::FETCH_ASSOC);


if ($row["username"]==$username){
    $errorMsg[]="Sorry but username already exsit";
}

else if ($row["email"]==$email){
    $errorMsg[]="Sorry but email already exsit";
}

else if($isset($errorMsg))

{

$insert_stmt=$db->prepare ("INSERT INTO masterlogin (username,email,password,root) VALUES(:uname,:uemail,:upassword,:urole)");
$insert_stmt->bindParam(":uname",$username);
$insert_stmt->bindParam("uemail",$uemail);
$insert_stmt->bindParam("upassword",$upassword);
$insert_stmt->bindParam("urole",$role);

if($insert_stmt->excute())

{

$registerMsg = "Register Succesfully...Wait Login Page";    

header("refresh:4;index.php");

   }

   }

 }

 catch (PDOException $e) {

echo $e->getMassage();

 }

}

}

?>

connection.php

<?php

$db_host="localhost";
$db_user="root";
$db_password= "";
$db_name="php_water tower 2000";

try {

$db=new PDO ("mysql:host={$db_host};dbname={$db_name}",$db_user,$db_password);
$db->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);

}

catch (PDOEXCEPTION $e) {
    $e->getMessage();
}

?>

logout.php

<?php
session_start();

header ("location:index.php");

session_destroy ();

?>

admin_home.php
<style type = "text/css">

body {
    padding:0;
    margin:0;
    background:
}
    

h1 {

font-size:5em;
margin:0;
padding:0;
text-align:center;
font-family: 'arial';
position:absolute;
top:50%;
left:50%;
transform: translateX(-50%);

}

</style>
</body>

<body>
<h1> This is the Admin Page </h1>
</body>


<?php

session_start();

if(isset ($_SESSION["admin_login"])) 
{
    header ("location:.../index.php");
}

if(isset ($_SESSION["parent_login"])) 
{
    header ("location:parent/parent_home.php");
}

if(isset ($_SESSION["swimmer_login"])) 
{
    header ("location:swimmer/swimmer_home.php");
}

if(isset ($_SESSION["admin_login"])) 
{
 ?>
Welcome,
<?php
echo $_SESSION ['admin_login'];

}
?>

<a href = "../logout.php">Logout</a>`

parent_home.php

<style type = "text/css">

body {
    padding:0;
    margin:0;
    background:
}
    

h1 {

font-size:5em;
margin:0;
padding:0;
text-align:center;
font-family: 'arial';
position:absolute;
top:50%;
left:50%;
transform: translateX(-50%);

}

</style>
</body>

<body>
<h1> This is the Parent Page </h1>
</body>

<?php

session_start();

if(isset ($_SESSION["parent_login"])) 
{
    header ("location:.../index.php");
}

if(isset ($_SESSION["admin_login"])) 
{
    header ("location:.../admin/admin_home.php");
}

if(isset ($_SESSION["swimmer_login"])) 
{
    header ("location:.../swimmer/swimmer_home.php");
}

if(isset ($_SESSION["parent_login"])) 
{
 ?>
Welcome,
<?php
echo $_SESSION ['parent_login'];

}
?>

<a href = "../logout.php">Logout</a>`

swimmer_home.php

<style type = "text/css">

body {
    padding:0;
    margin:0;
    background:
}
    

h1 {

font-size:5em;
margin:0;
padding:0;
text-align:center;
font-family: 'arial';
position:absolute;
top:50%;
left:50%;
transform: translateX(-50%);

}

</style>
</body>

<body>
<h1> This is the Swimmer Page </h1>
</body>

<?php

session_start();

if(isset ($_SESSION["swimmer_login"])) 
{
    header ("location:.../index.php");
}

if(isset ($_SESSION["admin_login"])) 
{
    header ("location:.../admin/admin_home.php");
}

if(isset ($_SESSION["parent_login"])) 
{
    header ("location:.../parent/parent_home.php");
}

if(isset ($_SESSION["swimmer_login"])) 
{
 ?>
Welcome,
<?php
echo $_SESSION ['swimmer_login'];

}
?>

<a href = "../logout.php">Logout</a>