Authors are as individual as any other group of humans. Some of them love interacting with fans and some don't. Some are active on social media on a daily basis, and some can't stand it and either hire someone to deal with it for them or just ignore it entirely. I would start by looking at what kind of public contacts they put out there. Do they have a website or social media presence? Do you see them regularly engage with readers online? Do they list a public-facing email address? If you can't track any of that down these days, probably the author doesn't do a lot of direct interaction with fans, but as a last resort you can always contact their publisher or agent and ask.