Not being prompted to continue after first challenge

I just finished my first challenge, changing “Hello” to “Hello World”, and I am not being prompted to the next one… I pressed Run Tests, and nothing. What am I doing wrong?

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/64.0.3282.140 Safari/537.36 Edge/17.17134.

Link to the challenge: