404 Page not found error
Make sure you have properly configured all the pages required by the plugin - as explained into this documentation section.
Make sure you have properly configured your site's permalinks - read here https://docs.posterno.com/article/500-profiles-permalinks.
In most cases the issue can be fixed by simply going in "Settings -> Permalinks" and re-save your permalink settings. The issue is usually caused by the activation/deactivation of a new theme/plugin on your site.
Possible other causes
- apache II mod_rewrite module is not being loaded by your web server.
- Your WordPress .htaccess file is missing or not writeable by the web server.
- Apache II is configured to disallow overrides by your .htaccess file.
- First make sure that mod_rewrite is installed and enabled on your Apache II web server, and also make sure that the webserver allows your .htaccess file to override the server directory configuration.
- Make sure that your WordPress .htaccess file is present in your WordPress installation. If it is not, simply create a blank file called .htaccess and upload it to your WordPress installation folder.
- Set permissions on your .htaccess file that allows your web server to write to the file – CHMOD 666.
- Go back and set your permalinks option to the “default” option and save the change. Then set it to something other than the default and save the change.
- If your .htaccess file is writeable by the web server, it will contain new directives that sets rewrite rules for your custom permalink option.
- If it is not writeable, you will see a message below your permalinks screen that contains the rule set you need to add manually into your .htaccess file, save it, and upload it back to the WordPress installation folder.
- If the issue persists, contact your web host support team for further assistance.
For additional information on working with permalinks in WordPress, visit the WordPress Codex http://codex.wordpress.org/Using_Permalinks