Error 405: Method not allowed. Web-app does not start

MIT App Inventor Help
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Hello everyone! I am a student and don't have the luxury of internet availability all the time. So, I downloaded offline App Inventor application for Windows.
However, when I run aiStarter.exe and go to the address 127.0.0.1:8004, it gives error : 405: Method not allowed.

I have tried to run the web application on Firefox, Edge, Brave and Opera but the result is same "405: Method not allowed".
I have also installed & tried app inventor on Windows 11, Windows 10 and Linux Mint but result is same.

How can I fix it issue and start the application?
Thanks

My post is blocked by a "superuser" without even giving it a consideration assuming that I have downloaded app inventor from some 3rd party. While, it was downloaded from here MIT official website. Here is the link,

http://www.appinventor.mit.edu/explore/ai2/windows

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Ask on their own support board.
(Wherever that might be.)

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