Link to a custom entity settings page does not appear at /admin/structure I have several custom entities as part of a module. When I visit /admin/structure, one of the entities is not listed in the groups of setting, or in the lists. However, if I manually type, /admin/structure/{entity}/settings/fields, I can manage the fields, form and display. However, the "Settings" tab is missing.

Similarly, I can manually type /admin/structure/{module}/{entity} to see the entity list, but the link is missing. The entity list is missing the button to add a new entity because the entire #block-seven-local-actions div is missing. Manually typing /admin/structure/{module}/{entity}/add brings up the correct form, and the form works.

It appears the routes are present, but something is preventing some of the links from being displayed. There are no errors in the recent log messages.
Please revise your file:  


  yourmodule.links.menu.yml.


and verify if exists the parameter


  parent


A complete example

  yourmodule.admin_content:
  title: Content
  description: 'Find and manage content.'
  route_name: system.admin_content
  parent: system.admin_structure
  weight: -10