Has anything changed regarding HTTP requests during the last couple of weeks, or last couple of sim rollouts? I ask because starting somewhere around 10 days to 2 weeks ago, about 1.25% of all my requests fail with a 502 error (or 499 error if it was a https request). This problem does not depend on load, script, time of day, day of week, or region: About 1.25% of all requests fail, spread out 24/7, with no discernable pattern to the failures.
I ran a test where I pinged my server every 30 seconds, for hour and hours on end, from a client outside of the AWS cloud, with no lost requests or errors at all. That same ping from inside SL results in the mentioned 1.25% loss due to 502 or 499 errors.
I don't know what to make of it, or how to troubleshoot it further.
The server setup is a dedicated linux i3-9100 server, running nginx, php, and mysql. The internet connection is a 50mb up and down fiber connection. It has been running with no errors for over a year (up until 2 weeks ago).