404 errors happen when you are looking for a page that does not exist. In WordPress, a rewrite array is created to manage permalinks and “pretty URLs”. Sometimes, Improperly coded plugins, custom posts types and taxonomy alterations can corrupt the permalink array, which causes the 404 errors.
Quick Fix:
You can rewrite your permalink array by going to your WordPress Dashboard → Settings → Permalinks, change the permalink type to post ID then Click “Save Changes”. Next, simply change it back to your original permalink structure.
More often than not, this will fix your 404 errors! If you are still experiencing issues with 404 errors, there may be a bigger issue and you may need to put in 301 redirects to the proper page.