Say Hello to HTML Elements i cant get passed this challenge test running doesnt seem to work

Tell us what’s happening:

Your code so far

<h1>Hello world</h1>

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 Edge/16.16299.

Link to the challenge:

Make sure you write exactly what it asks you to write.

you should write full sentence like Hello World see below

<h1>Hello world</h1> then run the code and never forget closing tags