FAQ page not found error

Hello

After deactivating and then reactivating the Arconix FAQ plugin,when I access each FAQ page, “404 Page Not Found” appears.
However, the FAQ shortcode works well I think.
Reference site: http://www.experiencingwmscog.com/faq/ (FAQ page — works well)
http://www.experiencingwmscog.com/sitemap/ (When you click each FAQ page, the “404 Page Not Found” error displays.)

How can I fix this error?

Thanks for your help.

https://ww.wp.xz.cn/plugins/arconix-faq/