Joining a community is hard. You go to a meetup, don't know anyone there, awkwardly introduce yourself to a few people, and eventually leave. Or you've been part of a community for a while but there always seems to be an elite clique in the group that doesn't seem interested in engaging with you. People just don't want to be your friend.
Why? It feels like a risk for someone to invest their time into meeting you, talking to you, and getting to know you. For elder members of a community, there are a ton of friends and associates they want to talk to at a meetup. When talking to the people they already know there is a guaranteed return on time investment – the strengthening of a relationship. But engaging with people new to a community has no guarantee on the time investment. The chances that the new person comes to one meetup and never shows up again are high.
This forms a vicious cycle. New people show up, have an awkward, uncomfortable experience because they don't know anyone, and then decide never show up again. This in turn validates the subconscious risk calculation the older members made in not talking to new people. The incoming community members keep churning quickly because the elder members are isolated, and they stay isolated because the new people don't stop churning.
So if you're struggling to join a community the best advice I can give you is to keep showing up. Every time you show up you are letting people know that you're there to stay. People will take notice (whether they know it or not), and the subconscious risk in building a relationship with you decreases. You can forget a new name only so many times. The bad news is that this just takes a while. It took over a year of showing up over and over again before I felt the Chicago game dev community began to know me at all.
It takes time, and it takes accepting that you'll be uncomfortable, but it'll be worth it. The communities I've been a part of have been invaluable to me both personally and professionally. So if you're new, keep showing up. And if you've been in a community for a while, do your best to welcome new people. It only feels like no one wants to be your friend.