My referrals are ineligible. How come?

hello, i sent invitation to many friends but every time after they completing registration and instalation app on their comps i get same result - Ineligible. 
We not connected to same network, not using same computers,  or something like that. I tried a lot of absolutly different people but every time same result. Can anyone help me pls?

i have basic verison. They try to instal mobile and desktop app but nothing work. Friends with status waiting for instalation have mob app and if they get desktop status changed to Ineligible