If I understand correctly, you are opening the Paramount+ app on the TV through your cable box (Contour) and trying to sign in using your phone/computer/tablet?
If this is what you are attempting, the TV will display the 5 digit code when Paramount+ and Cox are able to connect through your wifi/cable box
If you try to sign in using the TV, a keyboard will appear for you to enter your user name and password. What will likely happen next is the Paramount + main menu will appear and you will be signed in; However, this is what is happening next for many Cox customers: You select a show, it will appear with the option to watch and when you attempt to launch the show it will spin for a minute or two and a message will appear stating "Content can't be loaded" OR "Something went wrong, Try again Later"
I hope this makes sense
Good luck and patience until Cox and/or Paramount + get this resolved