My apps list: /user/1/apps ---> This links works fine. I could the list of my apps.
View APP info /user/1/apps/Dru8APP --> This link works fine. I could get the app details
Create APP /user/1/create-app--> link not works
Edit APP /user/1/apps/Dru8APP/edit--> link not works
Gives the default connection error configured at /admin/config/apigee-edge/error-page-settings "Cannot reach management server. An administrator should check the configuration of this site."
How can we resolve it
Check your "Recent Log Messages" and see if there's a more specific error. "Cannot reach management server" seems like your org credentials are not correct.