Hello,
it was brought to my attention a few months ago that a mac user was seeing the following pop up dialogue box in roundcube with some frequency:
connection error (failed to reach the server)
At the time, I was chasing a problem with apache where hundreds of connections would open up within a matter of a minute or two, maxing out the allowed connections, and causing roundcube to be unavailable for about 1 minute a few times a day. Didnt' take me long to figure out the IP causing the apache problem was the same user reporting the error pop up.
I never did figure out the root of the problem, but I suspected it had to do with the self-signed certs and the CA not being installed on the client's mac.
A while later, another mac user started reporting the same error popping up, and I saw the same spike in http connections from this user's IP addresses. Investigated more, got the CA cert installed on this mac, didn't fix the problem, ended up again with no solution.
Reloading apache always worked, but it was hard to be on hand whenever the connections spiked, so I wrote a little script that checks the number of connections and reloads apache when it gets over 400 connections. That solved the apache problem (bubblegum, I know), so I called it a mac anomaly put it on the back burner. the error popup didn't actually stop anything from working, just had to click it closed every few minutes, and my customers were amiable to doing just that.
Over the last couple of months, I have learned/seen that the same popup happens on ipads and windows computers as well. I just worked on one windows computer where the popup happened in chrome/firefox/IE, with the CA installed so there is no certificate error. Conversely, I use roundcube every where I go on a wide variety of computers, and I do not see this error very often, if ever (can't remember seeing it while logged into my personal account right now). I definitely cannot reproduce it on my ubuntu machine in the office.
Best as I can tell on google, the error indicates an http connection failure, but nothing actually fails to work. I can find nothing in the roundcube logs nor the apache logs, which I suppose is expected if the client is failing to connect to the server. The internet connections in my part of the world lack the speed the rest of the world sees; for example and average business/residential connection has a 512Kbps or 768Kbps upload speed, but surely just navigating in roundcube wouldn't flood that? The computer I was just working on is a few years old and a tad underpowered by modern standards, but for a minimal install of windows 7 it isn't sluggish, and cpu/RAM usage don't spike when roundcube is open. And the spike in http connections to the server did not happen, so I am not longer certain if that is related.
Does anyone have a suggestion on how I might track the cause of this annoying popup? Or at least cause it to stop popping up all the time?