title: Springboot swagger url does not work and shows WhiteLabel Error page
body: <p>I used spring boot swagger in my project.
  I added all the dependencies(swagger 3.0) and configuration file in my project.
  The project only contains simple routing, swagger dependency and configuration file works well and shows apis.
  But whenever I try to append these dependencies and configuration files to other project, it does not work at all.
  The Spring Boot version is the same in both projects(2.2.6.RELEASE).
  So it does not related to Spring boot version.
  I think there is other problem for that.
  Please let me know the possible cases.</p>