Troubleshooting a failed Event Connection, or, "Why isn't the screen updating when I do stuff?"

Owned by Tim McCune
Last updated: May 08, 2018 by Angie McCune
4 min read

Problem

There is an "Event Connection" to the server that sends events to the Monitor and Queue Manager in real-time as they happen, so that the UI can be updated.  If you're doing stuff like adding customers, summoning customers, removing customers, etc. and your actions are not being reflected in the Monitor or the Queue Manager, this is because you don't have an Event Connection to the server.  Note that the Monitor does continue to poll the server for various information every 60 seconds, in addition to the Event Connection, so if you're seeing customers appear there, but very slowly (i.e., only after up to 60 seconds has passed,) you do not have an Event Connection.

Solution


  1. The most common cause of this problem is having multiple tabs or browser windows open to multiple QLess URLs.  Your web browser enforces a maximum number of connections to any server that may be open at one time.  If your browser has several tabs or windows open to the same QLess server, there won't be any more connections left to be made to establish an Event Connection.  Note that different server names like merchant.qless.com, kiosk.qless.com, and monitor.qless.com count as different servers, so it's ok to have, for instance, one browser tab using merchant.qless.com, one using monitor.qless.com, and one using kiosk.qless.com.  Just don't use multiple tabs for the same host name.
  2. Does the problem still occur if you restart your browser?  Sometimes browsers can "leak" connections to a server after you close a tab or window, and you'll hit the same problem listed above.  Restarting the browser should close these leaked connections.
  3. Does the problem still occur if you clear your browser's cache and then refresh the page?
  4. Does the problem still occur if you restart your computer?  Sometimes, even if you think you've closed your browser, it may still be running (I'm looking at you, Internet Explorer).
  5. The default Event Connection works with (at least) Firefox, Chrome, Safari, Android Browser, and Internet Explorer 7 (and ONLY version 7).  It does NOT work with IE 6, IE 8, or IE 9.  We have built a "beta" Event Connection that works with IE 8.  If the server detects that you're using IE 8, it will automatically redirect you to the beta URL.  The beta Event Connection will also work with Firefox, Chrome, and Safari, and it uses a completely different mechanism for connecting to the server (WebSocket instead of HTTP).  The beta URLs are https://merchant.qless.com/qless/merchant/beta (Queue Manager), http://monitor.qless.com/qless/consumer/monitor/beta (Monitor), and http://kiosk.qless.com/qless/consumer/kiosk/beta(Kiosk).  So, knowing that,
    1. If you are using Internet Explorer...
      1. Version 6 or lower: You're out of luck.  QLess will not work with your browser.  Try Firefox.  And yell at whoever won't let you upgrade.
      2. Version 7: Make sure you are NOT using the beta URL.  IE7 is also notorious for "leaking" connections.  By default, IE7 will not allow you to have more than 2 connections open to the same server at the same time.  Sometimes closing the browser window will not also close the connection to the server, and the connection remains open and "leaks".  Then the next time you open a window to that same server, you're down to 1 connection available to you, to keep you under the limit, until you completely restart Internet Explorer.  Because of IE's tight integration with the Windows operating system, this will sometimes require a complete reboot.  The good news is that there is a way to increase the limit on the number of connections that can be opened to the same server at the same time.  Instructions for this can be found at http://support.microsoft.com/kb/282402 and we recommend increasing the limit to at least 10.  We also recommend rebooting a computer that is using IE7 once per day, to limit the impact of these leaked connections.
      3. Version 8 or higher: Make sure you ARE using the beta URL.
    2. If you are using Firefox, and you are not using the beta URL, try it.  If you're using the beta URL, try the non-beta URL.
    3. If you are using Chrome, Safari, or Android Browser...
      1. If you're not using the beta URL, try it.  If you're using the beta URL, try the non-beta URL.  Still no luck?  Try Firefox.
    4. If you are using another browser...
      1. Report the issue at https://support.qless.com.  Then try Firefox.
  6. If you have any antivirus software installed on your computer, try disabling it.
  7. If you have Windows' firewall enabled, try disabling it.
  8. If you're behind a proxy, see if there's any way to circumvent it.  Some proxies can cause problems with both versions of the Event Connection.
  9. If you're behind a firewall that restricts your access to only certain ports, and you're using the beta Event Connection, this may be blocking your access.  Our beta Event Connection connects on port 8000.  Talk to the person running your firewall and see if you can get port 8000 opened to merchant.qless.com.
  10. Still no luck?  Report the issue at https://support.qless.com and include the list of all browsers and versions you've tried, which URLs you've tried, which operating systems and versions you've tried, information about how you are connected to the Internet (any proxies or firewalls that may be in the way,) and the steps to reproduce the problem.