The notorious error 404 is caused by two different scenarios. It is usually caused by either a WordPress site being taken down or removed. Or more likely, it is due to an error with WordPress permalinks.
The Permalinks configuration (General Settings) is the most likely culprit for 404 errors. If you have recently changed your hosting, migrated your website, or changed the domain name there is probably an inconsistency between the old version of your site and the new one.
Settings > Permalinks. From here, you can check if the URL structure matches what you expect. Also verify that the domain name is correct. After making the changes, be sure to hit the “Save Changes” button or the changes won’t go live.