I have a managed app in a Dev Org. Now I want to connect it to my main Org. I followed the instructions described in the posting "Can we connect dev org with Environment Hub?". I went to the Environment Hub and selected Connect Org, then I enter the system administrator username on the Dev Org. The window that popups up shows the following message. The message refers to a redirect_uri which is mismatched, however, I don't know what I am supposed to set or where to set it.
error=redirect_uri_mismatch&error_description=redirect_uri%20must%20match%20configuration
click-path in the Environment Hub: Setup | Apps | App Manager | choose 'Environment Hub' Connected Apps