PHP when refresh page ,browser remove a session - php

Question

I don't know exactly how to explain ...
When I log in, on a browser page, enter the correct user, but if I open another page, still in the browser in use, and I refresh it automatically chooses one of the two users, deleting the other
I don't know if I have explained myself well, I don't know how to explain myself well. excuse me
This is a private page code (page after log in)
session_start();
function authenticate()
{
return array_key_exists('email', $_SESSION);
};
if (authenticate() !== true) {
header("location: /private/login/log-in.php");
}
$user_id = $_SESSION['id'];
$email = $_SESSION['email'];
$password = $_SESSION['password'];
$check_id = "SELECT * FROM usertable WHERE email = '$email'";
$result = mysqli_query($conn, $check_id);
if (mysqli_num_rows($result) > 0) {
$fetch_info = mysqli_fetch_assoc($result);
$user_id = $fetch_info['id'];
};
This is a login code
session_start();
$user_id = $_SESSION['id'];
$email = $_SESSION['email'];
$password = $_SESSION['password'];
$check_id = "SELECT * FROM usertable WHERE email = '$email'";
$result = mysqli_query($conn, $check_id);
if (mysqli_num_rows($result) > 0) {
$fetch_info = mysqli_fetch_assoc($result);
};
if (isset($_POST['login'])) {
$email = filter_var($_POST['email'], FILTER_VALIDATE_EMAIL);
$password = md5($_POST['password'], FILTER_SANITIZE_FULL_SPECIAL_CHARS);
date_default_timezone_set("Europe/Rome");
$date = date('Y-m-d H:i:s');
$sql_insert_date = mysqli_query($conn, "UPDATE usertable SET activeLogInDate = '$date'");
$check_email = "SELECT * FROM usertable WHERE email = '$email' ";
$res = mysqli_query($conn, $check_email);
if (mysqli_num_rows($res) > 0) {
$fetch = mysqli_fetch_assoc($res);
$_SESSION['id'] = $fetch['id'];
$uniqueID = $fetch['uniqueID'];
$username = $fetch['username'];
$name = $fetch['name'];
$fetch_pass = $fetch['password'];
if (password_verify($password, $fetch_pass)) {
$activeStatus = "Online";
$sql2 = mysqli_query($conn, "UPDATE usertable SET activeStatus = '$activeStatus'");
$_SESSION['email'] = $email;
$status = $fetch['status'];
if ($status == 'verified') {
$_SESSION['email'] = $email;
$_SESSION['password'] = $password;
header("location: /private/private_page/private.php?us=$uniqueID?nm=$username");
} else {
$info = "Non è stata verificata la tua identità,controlla il messaggio inviato all' email $email";
$_SESSION['info'] = $info;
header('location: /private/otp/otp-code.php');
}
} else {
$errors['email'] = "Inserimento password o email non corretto!";
}
} else {
$errors['email'] = "Sembra che tu non sia ancora un membro! Clicca sul pulsante registrati per iscriverti.";
}
};

Answer 1

The line -
$password = md5($_POST['password'], FILTER_SANITIZE_FULL_SPECIAL_CHARS);
is incorrect. md5()'s second parameter is meant to be a bool; you've got a likely copy/paste/edit error from the previous line, filter_var();
Take out the second parameter.
BTW you shouldn't really rely on md5 these days. There's a password_hash() function that's what you should be using now.