There are times where your main website will load but when you go to additional pages you reach the dreaded 404 error. Traditionally a 404 error means that a page is missing (such as when something was deleted or renamed). WordPress does some tricky stuff to make fancy URLs called Permalinks and we often find sometimes this setting gets lost causing the 404 error.
To fix this error login to your WordPress install and go to Settings > Permalinks. On this page you can simply scroll down and click Save.
That should be enough to make the permalink setting fix and additional pages on your site should now be loading. If for some reason you continue to have issues don't hesitate to reach out via support ticket!