404 Not Found
404 Not Found would be relatively indicated that the requested web page was not found, for example below:
It could have due to the wrong permalinks structure and thus, the missing page therefore, may opt for reset the .htaccess as below:
The .htaccess file is a basic configuration file used by the Apache web server. You can use it to set up redirects, restrict access to all or some of your site.
You may access to the File Managar or FileZilla to locate and backup the existing .htaccess. Once done, you may logon to your WordPress admin backend:
Go to Settings → Permalinks in your WordPress dashboard
Click Save Changes at the bottom of the page (you do not need to make any changes – just click the button)