This page doesn’t seem to exist.

Hi there,

Seems you don’t have the plugin enabled since the shortcode is not working. Let me know once you’ve enabled it, so I can have a look at it and provide you help.

Regards.

Excuse me. I deleted the plugin to try the others. I installed it again, but the error did not disappear.
https://vlvnt2018.jinr.ru/participants.html

I checked everything according to this page https://docs.wpusermanager.com/article/72-404-page-not-found-error but still it not working.

We already dealt with the problem – it was plugin “.html in url”. Now everything works fine, your plugin is the best!

Glad you solved the issue, if you have any other questions, let me know ??