In working with clients or dealing with friends, always a good policy to
Respect Others' Boundaries Cause It Is The Mature Thing To Do.
We build rapport with people as we know them better and earn trust. But inevitably if you naturally are a too much information sharing kind of person yourself with them or just a highly curious "busy body" even kind of person you almost expect reciprocity of answers to your questions.
Not only is this not polite but you are disrespecting another person's boundaries that maybe they have told you all they want to tell you about something, so like my Koala bear inching forward to grab another eucalyptus leaf,
MAYBE IT IS TIME TO BACKOFF.
Sharing needs to be tested where you drop shields and if they don't correspond dropping some more of their shields either they are inherently a more closed person than you, or you have hit the limit of their divulging to you.
This is all about RESPECT. Read adults well, children or your partner, significant other, or spouse are a different matter with a "need to know." Don't push boundaries.