Put in my mac and got authorization failed so I changed my mac via there webpage and it still says authorization failed. I'm using kodi 15.2 and stalker 9.0.21. I have even tried kodi 16 rc1 and have the same issues.
IPTV Stalker's current life span is limited, expiring on 1 Feb when a username/password is required. Someone may update it to include the passing of a username/password, but as things currently stand, it can't.
You're better off configuring the Kodi native PVR Stalker Client or PVR Stalker NFPS. They both have username/password functionality. Check out stickies for configuring either of these optiobs.