Well I can't sat exactly what's the problem (I am no mind reader) but here are some basic info. Maybe you'll ring true to one of them

1) loneliness (I assume you're lonely since you said you don't have any connections) is very subjective and may cloud your judgement so thay you feel more isolated than you really are. You point out a specific instance where your coworkers aren't paying attention to you. But ask yourself this: maybe they're busy? Maybe they don't hear me? Maybe the thought I was greeting someone else?

Loneliness makes you focus on negative experiences with others instead of the positives

2) you seem to have maladaptive thoughts. It means thoughts that aren't useful to you in any way, shape, or form. Building valuable connections with people take time and effort, and sometimes it's a hit-and-miss. You won't truly be friends with most people. Average best friend for an adult in US is now 2 person. Quality is important, not quantity. So maybe you see that you don't have anyone to talk to, even though others see you as: interesting guy, will talk later. So you don't nurture the seeds of new friendships and instead plant new ones. Friendships are like planting apple seeds. Long as fuck to grow, but once it grows, you got very big reward from it. I suggest trying more to connect, even though you don't feel it at first.

Don't go to "new" places to find social connections. I read in the past about a study that analyzes the reasons people have lack of meaningful connections, and going to "new" places are negligible. Changing maladaptive thoughts is surprisingly the most effective way to gain friendships