First, confirm that the tournament URL is correctly typed. If you're able to access the page but other users get "404 - Page Not Found", this typically means the page wasn't published.
To publish your page, make sure that the tournament visibility is set to Public and not Admins Only!
For more information on Publishing Options, check out the following article here: Publishing
If you are just trying to access the page as an admin but are getting this error, make sure you are logged into the correct account that has admin privileges. You can check this under the Admin Permissions page.