Page doesn’t exist

Hi! There’s something strange happened. When I click on the menus in the dashboard: courses, achievements …. edit account, I see the page that says that Page doesn’t exist. For example, I click edit account, I see thepage with endpoint ‘edit-account’ but says ‘Page doesn’t exist’. The same with other menus in dashboard. Also, when I try to preview ‘Edit Account Information’ in ‘Forms’ I see the same page with text ‘Page doesn’t exist’. Do you know why it happened? Thanks for your time!