Cannot use live studio code

I am new to Live Studio Code.
Have a developer who started creating a design of my website. I was not comfortable with this new way of creating my website at first but now I like it.
However - in a new updated version of my new design I cannot see Open live website.

I have a version of my new htm design which I can view in Live Studio code. I have newer versions which I cannot open and view in open live server. It only shows directory.

Developer says that all is fine at his place but as mentioned it is not fine at my place. Shows http://127.0.0.1:5500/

What is wrong and how can this be corrected?

Thank you

Best regards,

Margit Cathrine