I am trying to build a flask app in which users can choose a pseudo and chat in one_to_one chat randomly with skip option , the problem here is that when user choose his username and redirect him to waiting page , it still stuck in there even when i open the website in an other browser (trying it on localhost and working on pychram)

(https://i.sstatic.net/MBnK1UGp.png)

import random
from flask import Flask, render_template, request, redirect, url_for, session, jsonify, send_from_directory
from datetime import datetime
import os

app = Flask(__name__)
app.config['SECRET_KEY'] = 'your_secret_key'
app.config['UPLOAD_FOLDER'] = 'uploads'
os.makedirs(app.config['UPLOAD_FOLDER'], exist_ok=True)

messages = []
users = []
pairs = {}

@app.route('/')
def choose_username():
    return render_template('index.html')

@app.route('/set_username', methods=['POST'])
def set_username():
    username = request.form['name']
    session['username'] = username
    users.append(username)
    session['paired'] = False
    return redirect(url_for('chatroom'))

@app.route('/chatroom')
def chatroom():
    if 'username' not in session:
        return redirect(url_for('choose_username'))
    pair_user()
    return render_template('chat_room.html', messages=messages, username=session['username'], paired=session['paired'])

@app.route('/logout', methods=['POST'])
def logout():
    username = session.get('username')
    if username in users:
        users.remove(username)
    if username in pairs:
        partner = pairs.pop(username, None)
        if partner:
            pairs.pop(partner, None)
    session.pop('username', None)
    return redirect(url_for('choose_username'))

@app.route('/send_message', methods=['POST'])
def send_message():
    if 'username' not in session:
        return redirect(url_for('choose_username'))

    name = session['username']
    message_text = request.form['message']
    timestamp = datetime.now()
    file = request.files.get('file')
    file_path = None

    if file:
        filename = f"{timestamp.strftime('%Y%m%d%H%M%S')}_{file.filename}"
        file_path = os.path.join(app.config['UPLOAD_FOLDER'], filename)
        file.save(file_path)
        file_path = os.path.join('uploads', filename)

    new_message = {'name': name, 'message': message_text, 'timestamp': timestamp, 'file_path': file_path}
    messages.append(new_message)
    return redirect(url_for('chatroom'))

@app.route('/uploads/<filename>')
def uploaded_file(filename):
    return send_from_directory(app.config['UPLOAD_FOLDER'], filename)

@app.route('/check_pairing')
def check_pairing():
    username = session.get('username')
    paired = session.get('paired', False)
    return jsonify({'paired': paired})

@app.route('/skip', methods=['POST'])
def skip():
    username = session.get('username')
    if username in pairs:
        partner = pairs.pop(username, None)
        if partner:
            pairs.pop(partner, None)
            clear_messages(username, partner)
    session['paired'] = False
    pair_user()  # Pair the skipping user with another random user
    return redirect(url_for('chatroom'))

def pair_user():
    global pairs
    if len(users) >= 2:
        available_users = [user for user in users if user not in pairs]
        if len(available_users) >= 2:
            user1 = random.choice(available_users)
            available_users.remove(user1)
            user2 = random.choice(available_users)
            pairs[user1] = user2
            pairs[user2] = user1
            session['paired'] = True

def clear_messages(user1, user2):
    global messages
    messages = [m for m in messages if m['name'] not in (user1, user2)]

if __name__ == '__main__':
    app.run(debug=True)

what i am expecting is when entering username if there is available user they will be paired directly and open chatroom for both of them and when one of them skip he will be paired with anyone else online
thank you