ModuleNotFoundError: No module named 'flask' and vitualenv Activate.ps1 cannot be loaded

Question

I was trying to create a Flask app in my virtual environment on Windowns 10.

I've created the environment using python -m venv flask_ven

In VS code, Python:Select Intrepreter, I chose Python 3.7.5("flask_evn":venv)

I have a simple code to test the connection

from distutils.log import debug
from flask import Flask

app = Flask("mpg_prediction")  ## give it a name

@app.route('/', methods=['GET'])  ## test if the app is working
def ping():
    return "Pinging Model Application!!"

if __name__ == '__main__':
    app.run(debug=True, host='0.0.0.0', port=9696)

But I tried to run it, it says flask is not installed.

I tried pip freeze in the terminal, then it says flask is installed Flask==2.1.2

I'm so puzzled.

When I was activating the virtual enviroment, I did come into an error

PS C:\Users\CSu.CL\Desktop\fuel consumption> & "c:/Users/CSu.CL/Desktop/fuel consumption/flask_env/Scripts/Activate.ps1"
& : File C:\Users\CSu.CL\Desktop\fuel consumption\flask_env\Scripts\Activate.ps1 cannot be loaded because running scripts is disabled on this system. For more information, see 
At line:1 char:3
+ & "c:/Users/CSu.CL/Desktop/fuel consumption/flask_env/Scripts/Activat ...
+   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : SecurityError: (:) [], PSSecurityException
    + FullyQualifiedErrorId : UnauthorizedAccess

Has it got anything to do with not finding flask?