Do you have only the MAC and donation fields filled in? Those are the only fields that need data now for Stalker Client.
If you checked and are certain there are no typos and you don't have any other fields filled in, then try using Simple Client. If you have Potato TV, it can fill in your Simple Client pvr settings for you. Disable Stalker Client and Enable Simple Client. Open Potato TV and click on pvr. Then follow the prompts and reboot Kodi.