Family Premium problems!

[gxfn]

I have a family premium, and currently I have 4 other members in it. I am currently trying to register one more member but there are some problems with the address. We live in the same address, but his account seems to fail to join the premium everytime. 

It was okay for quite awhile, but I am not sure what happened in between and now he is out of the premium package. 

Is there a way for me to check if all the addresses sync? So that the new member can also input it in the same way? How does Spotify verify the addresses? I tried to check under my profile and its only the postal code is shown. 

Help!