Finding first 1k users for a social/networking platform

A couple of days ago, I finally launched a beta version of a new platform that lets people network and connect by simply describing what they are looking for (in plain text). The platform then connects users whose search requests match/complement each other. Think of a Google search that indexes people’s intentions to network, meet, collaborate, or pursue activities together. Now, I'd like to validate the idea and gather some feedback. The problem is that I'd ideally need at least several hundred users (ideally a thousand or more) because if the pool of users is tiny (let's say 40 users), the likelihood of them finding each other is pretty low (unless they search for very similar things). I knew this would be one of the most challenging issues when I worked on the idea. People who gave me feedback also mentioned that the hard part would be to get some critical mass of users to have some pool to generate matches/connections. So now I'm wondering if there are any good ways to fairly expose the product to a broader audience (I don't want to use ads or spam people; I'd like it to grow organically and adjust the product as it grows). I tried Reddit, but finding the right subreddit is challenging. I realized that posting on subreddits dedicated to large metro areas (NYC, etc.) is prohibited as it falls under self-promotion. This applies to most moderately large [and relevant] subreddits. Then I tried thinking of where the "large enough" group of people who need networking and connections might be and realized that these could probably be some local expat groups and international student organizations (most complaints about the complexity of networking, connecting with others, building meaningful connections that I've heard so far, were in fact from people who moved places, cities, countries). Does my approach sound sane? Would you approach things differently? Also, I know that this is one of the reasons why most social and networking apps fail (according to Y Combinator, their fail rate is pretty high).