One PAR reverse proxy is not responding

(All times UTC)

• At 20:10 one of the 4 reverse proxies on zone PAR stops responding to some requests. No internal metrics changed, no weird logs were written. The requests would just time out. The other three were still running, so the requests errors were random.
• At 20:25 it stops responding at all.
• At 20:40 our external monitoring tool alerts us. We investigate, find which reverse proxy failed, restarted it.
• At 20:43 the reverse proxy is restarted and traffic goes fine.