Blank page after php header redirect

I recently tried to modify my httpdocs/index.php file to redirect all traffic to another page using the Location command.

This worked fine, and all page traffic was redirected.

However, after a few minutes I decided this wasn’t going to work and removed the command, restoring the file to its original.

Now my site simply renders as “Done” without anything being displayed on the page. No source code. I can edit the files, see the posts and comments in the Admin panel. But when I click “View” the site simply doesn’t render at all.

I’m very certain that I have not made a syntax error. What else could have caused this issue and how can I fix it?

Thank you very much.