A 404 error tells you that the page or file you are trying to open can't be found. If you have a lot of 404 errors on your WordPress site, then this is often due to an issue with your permalinks. Follow the steps below to fix this.
- Log in to WordPress admin.
- Click Settings > Permalinks in the menu on the left.
- Click Save Changes at the bottom of the page.
- Click Purge Performance Cache at the top of the screen, if you have this enabled. Do the same for other caching plugins you may have.