 <p>Don't use Flask's development server in production. Use a proper WSGI server that can handle concurrent requests, like <a href="http://gunicorn.org/" rel="nofollow" title="Gunicorn">Gunicorn</a>. For now try turning on the server's threaded mode and see if it works.</p> <pre><code>app.run(host="x.x.x.x", port=1234, threaded=True) </code></pre>