I noticed that some of my user accounts are unable to login to the control panel and when I looked at the logs I saw there is a missing sock file as shown here
[crit] 16544#0: *8 connect() to unix:/usr/local/cwp/php71/var/sockets/testuser.sock failed (2: No such file or directory) while connecting to upstream, client: #.#.#.#, server: localhost, request: "GET /testuser/ HTTP/1.1", upstream: "fastcgi://unix:/usr/local/cwp/php71/var/sockets/testuser.sock:", host: "srv.domain.com:2083"
All users logging to the control panel have a sock file created here /usr/local/cwp/php71/var/sockets/ but I realized my user with the issue doesn't have a sock file there. Initially, since it was a test user, I deleted and re-created the account and the sock file was created but after a while, it was gone again. Now it is happening to real users and they cannot log in to the control panel. They are getting errors like "502 Bad Gateway"