I don't know why SharePoint list filter web part doesn't show on the page once I add it. I opened web part in maintenance view and it is there, but not showing on the page.
I appreciate the help.
Append "?contents=1" to the url of the page to check if the web part exists on the maintenance page of the page. If it doesn't exist, it should be deleted by someone.
If it exists on the maintenance page, you need to make sure the web part is not hidden or closed. Disappeared web part