I found this article by @alvises that seems to shed some light in the settings that we can tweak:
From the version 1.4, Phoenix uses Cowboy 2 which has a new set of timeout options:
request_timeout( default 5_000 milliseconds ), *Time in ms with no requests before Cowboy closes the connection.- This is the maximum time, in which the client has to send the HTTP request. We do not touch this.
inactivity_timeout( default 300_000 milliseconds ), Time in ms with nothing received at all before Cowboy closes the connection .idle_timeout( default 60_000 milliseconds ), Time in ms with no data received before Cowboy closes the connection .
