The installer created the "SDLWebTridioncm_MAN01SQL05" CM environment for you (it asks you for the name in one of the screens). Since then, apparently someone decided to clear or recreate your Topology Manager database -- so it lost the information again. The Topology Manager website hasn't been restarted either, so it thinks it still exists.
Anyway, since you have a clean database you'll want to recreate this CM environment through the Add-TtmCmEnvironment cmdlet. I recommend using the same name so you don't have to modify anything else. You may have to restart the Topology Manager website first.