Hi @supernabhya17 The error may be raised due to “no” or empty filename. Your filename contains only extension(.html).
For example you an try to name it “index.html” as it is used to represent your first html page or default page.
You can name it anything rather than index.html but make sure it ends with .html extension.
thank you for the information
To save it , follow the following steps -
name the file index.html
then go to file menu on sublime text and then click on save .
YOUR FILE WILL BE SAVED !