report doesn't show up in sample application

Hi, newbie here. Maybe this is a simple question ,but I really got stuck on the problem. 

I'm trying to set up a sample application with python and flask, and have succesfully figured azure and power BI by following this tutorial "https://www.youtube.com/watch?v=FZjQmvwBAdU".

The issue is that after I run "python -m flask run",  the report icon keeps twinkling until it says 

Error Details:
Error retrieving Access token
HTTPSConnectionPool(host='login.microsoftonline.com', port=443): Max retries exceeded with url: /a9a8ba85-6f1d-457f-a989-e89ddbd2f367/v2.0/.well-known/openid-configuration (Caused by SSLError(SSLError(1, '[SSL: WRONG_VERSION_NUMBER] wrong version number (_ssl.c:1091)')))

The content in the index.html shows correctly though.

Did I miss something here?     Please give me some advice or an tutorial about it. Thanks a lot