SQL Server Reporting Services 2017 Cant connect and doesnt show in Configuration Manager
Have you done all the required steps of the installation? 

Could you compare your steps with this link post?
Installing SQL Server Reporting Services 2017 (MSSQLTips.com)
Do you notice any differences? 

Also check this resource:
What’s New in Reporting Services (SSRS) 2017 (SQLShack.com) 


  ...because if you try to connect to a SQL 2017 Reporting Services instance or Power BI Report Server instance with anything less than Management Studio 17 (grab it, its free!) you’ll receive this nasty error:   
  
   
  The error message on the web site resembles your own error message  
  
  Don’t worry, your instance is there &amp; (likely) online. Once you have SSMS 17 or higher you’ll be able to connect ...