Your solution is not correct as you may have guessed.
The original code provided was: <h1>Hello World</h1>
And the instructions given were:
Find the h1 element and change its text to:
CatPhotoApp
Make sure that the text is between its opening and closing tags.
The part you may have misunderstood is “Find the h1 element and change its text”
In the code given by the exercise the <h1> element’s text is actually the words Hello World.
So you need to erase those words and replace them with the words provided: CatPhotoApp