Sample project - two ASP.NET core web applications share same token generated from Identity Server 4.
Requirement: Visual Studio 2017
Launch all three applications - Web Application, Web Service and Identity Server.
If anonymous user browses a password protected page, s/he will be redirected to Identity Server.
After successful login, user is redirected back to the web application with authentication token.
Web application can now access web service using same token generated by Identity Server.