Closing Main tag?

It says that the closing main tag should come after the second closing paragraph tag, and it is! It’s still wrong!
What I have now is:

<p>Kitty ipsum dolor sit amet, shed everywhere shed everywhere stretching attack your ankles chase the red dot, hairball run catnip eat the grass sniff.</p>
<P>Purr jump eat the grass rip the couch scratched sunbatheshed everywhere rip the couch sleep in the sink fluffy fur catnip scratched.</P>

What am I doing wrong?

remember that in coding lower case is different from upper case

if this hint is not enought post again and I will be more explicit

It is valid syntax, but not best practice.

8.1. Writing HTML documents

Many strings in the HTML syntax (e.g., the names of elements and their attributes) are case-insensitive, but only for uppercase ASCII letters and lowercase ASCII letters. For convenience, in this section this is just referred to as “case-insensitive”.

The test is just not set up to handle it. Which is probably for the best just to teach best practices. You should keep your HTML tags/elements to lower case.