How to obtain a better interaction between members ?

Great question! I think this is a common theme for many communities. It feels like sort of a chicken/egg situation; if not many people are sharing/answering broad questions and generic discussion themes, not many people will become motivated, inspired or feel confident in starting to do so.

So what you want to do, is lead by example (content strategy) or at least reward the few good examples that dare to kick it off (activation). How? Perhaps by looking for ways of actively participating in such discussions, possibly also with non-moderator accounts. You could also start promoting/highlighting such great topics by actively sharing them, either by pinning them as sticky, through newsletter digests (perhaps to a subset of community users, either very active or recently registered), tagged in frontpage/sidebar widgets or pushed through dynamic content integrations (API-powered) across other digital channels. Influencing visitors on your main website, FAQ, mobile app and so forth with engaging community discussions will not only draw community traffic and increase time on site, but will indirectly also contribute to higher brand NPS - due to social proof, thought leadership and authenticity principles. In the end, everyone wins.

By moving into this direction, customers will gradually start recognizing this broader use case of your community and validate whether that's compelling, fun and worthwhile. And while you're making progress, gamification elements (ranks, badges, reputation indicators) can further accelerate your actions by encouraging and motivating the key players. So be sure to optimize these tools along the way!

Thank you for your answer, Rens ! We are already workng on it, and will keep you informed for sure !