Refferrer id is missing. Suddenly it is all gone. No user has refferrer.

Thank you for the reply...

I tried to install fresh joomla and instal alta user point. Tried to register some members and the referral id is gone after saving that user. It is a fresh install. If you said it is some misconfiguration on rule changing, can you help me, which rule do i need to configure and how to configure it correctly?

May be it is easier for you to understand my problem by doing these steps:
1. instal fresh joomla.
2. install alta user point.
3. Register a member.
4. register a member to be a downline.
5. go to user menu in alta user point component in administrator area, and klik the user as downline and then save it. The referral id is gone.

Which rule do i need to configure?

By the way, i really appreciate your reply.

Thank you.