I was getting stuck into my WordPress website and going along quite nicely until I decided to go to Settings > General and change the URL.
It wasn't a major change, in fact, it probably was unecessary. However, I added "www." to both the WordPress Address field and the Site Address field and saved changes.
Unfortunately now when I visit the site it does not work so I changed it back so both fields did not include "www.", but the website still does not work.
Why is this causing such a problem?