How to deal with the problem 'Tunnel 153bbde33b1d.ngrok.io not found'

[zhgqcn]

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[zhgqcn]

from google.colab import drive
drive.mount('/content/drive')

!pip install flask-ngrok
!pip install pyngrok
!pip install flask==0.12.2

# flask_ngrok_example.py
from flask import Flask
from flask_ngrok import run_with_ngrok

app = Flask(__name__)
run_with_ngrok(app)  # Start ngrok when app is run

@app.route("/")
def hello():
    return "Hello World!"

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