There is a difference between a:
Supervisor, provided the ability to monitor an agent via PBX observe. No web client access
Supervisor/web client user, while creating or modifying the supervisor the is an option to create a login ID for the web client with its password. Care should be used not to create it both in CCM and access and partitions. The easiest way to determine this is if has a user name there. Partition assignment still needs to be completed but the user will show up there.
Web Client user, The user is created in access and partition management.
Hope this helps