I'm new to interviewing. At this point, I've interviewed 5 candidates for the small startup I work at. I like to hear about projects the candidate worked on previously and then ask them to get into the technical details on a component of it. For example, let's say the candidate was scraping web pages for photos of cats. I'd ask them to tell me about it and the candidate starts with an overview of the system. Something like - "We built a process to scrape a set of webpages looking for cat photos. We then store the photos in an s3 bucket and retrieve them later via an api we built out". I'd then ask, "How are you identifying photos of cats on these webpages?". I'll get a fairly generic response, "Deep Learning", or "Photo Titles". I respond to this with, "That's interesting, tell me about the challenges you faced trying to implement that?". This is where I've received a deflection twice in the five interviews I've done. The first time this happened, the candidate responded, "That's too complicated". The second time the candidate responded, "I don't want to bore you with the details".
This is starting to concern me. When this happens in an interview, how do you get around it so the candidate will talk about the technical aspects of their project? Should this be an immediate red flag? Could I be doing something which leads to candidates not wanting to get into technical details?