This worked better for me too, so far. But it may depend on what the OP is working on. I'm in a similar situation as the OP, and asked people I know if they know anyone in the target or related fields. And then further asked those people if they knew anyone, at the end of the call. I'm still in the middle of this process right now, so let's see how it goes.

I don't ask if they think my product is a good idea. I ask questions about how they work, delve deep into the mundane details of their work, understand what the challenges are. Finally I make my own assessment of whether my product will truly be valuable to them. I do plan on pitching to some of them later, once I've a fairly good understanding of how my target users work.

Importantly, I was clear with everyone (including my friends) that I wasn't selling or pitching anything, and that my goal was to understand how the target users work. The product idea I have is just the context explained in the first 2-3 mins, the rest of the call is just listening and understanding their workflow. The conversations usually tend to be 30 mins to 1 hr.

+100 for 'Four Steps to the Epiphany'. All of what I did above was lifted straight from that book. I've been internalizing it for years, and still fail to follow it properly. It's an amazing book :)