You’ve got an extra space at the beginning of the URL that the tests don’t like.
In general, I would avoid adding extra spaces anywhere they are not needed. While technically the extra space here won’t stop the link from working in your browser, it is not a best practice to have a space there and you would never do that in real production code. So get in the habit now of not adding these spaces.
I would also check the nesting of your <a> tag
It’s on the same level as your <html> tag and probably needs to be tabbed over twice and nested within your <main> tag.