SSL_write() failed (55: No buffer space available) while proxying upgraded connection

[johan.belin]

I am a beginner so I am sorry for lacking info or stupid questions!
Building a WebRTC streaming media system based on mediasoup, the server runs
on a MacMini M1 in node, nginx port forwards to 8400. We are doing load
tests and at 120 connected clients nginx gives the following error message:
2021/11/03 19:10:07 [crit] 282#0: *659 SSL_write() failed (55: No buffer
space available) while proxying upgraded connection, client: 35.187.32.242,
server: idol.activeent.co, request: "GET /idol-server/ HTTP/1.1", upstream:
"https://127.0.0.1:8400/", host: "idol.activeent.co"
Then after that there is another error
2021/11/03 19:10:11 [alert] 282#0: *771 socket() failed (24: Too many open
files) while connecting to upstream, client: 23.251.143.177, server:
idol.activeent.co, request: "GET /idol-server/ HTTP/1.1", upstream:
"https://127.0.0.1:8400/", host: "idol.activeent.co"
Any suggestions what it can be and what to do about it?

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,292750,292750#msg-292750