Troubleshooting printing problems

Owned by Tim McCune
Last updated: Feb 25, 2016 by Angie McCune
2 min read

Problem

QLess Kiosk is not printing paper tickets.

Solution

After each step, check to see if printing is working.

  1. Ensure that the printer has paper.
  2. Check that the paper is not jammed, and clean out any loose paper from inside the printer.  A can of compressed air can be used to clean the printer if needed.
  3. Reboot the printer and try again.
  4. Refresh the web page and try again.
  5. Restart the browser and try again.
  6. Reboot and try again.
  7. Ensure that Java is installed.  If it is, report back to QLess Support the version that is installed.  If it's not, download and install it from http://www.java.com.
  8. Ensure that the Java Plugin is installed in your browser.  http://www.java.com/en/download/installed.jsp  If it's not, download and install it from http://www.java.com.
  9. Ensure that you can print a test page at the OS level.  For instance, in Windows, this can be done from the Control Panel.  If you can't, contact your printer vendor to troubleshoot.
  10. Enable the Java Console and restart the browser.  http://www.java.com/en/download/help/javaconsole.xml
  11. Try to print from within the QLess UI
  12. File a new issue at https://support.qless.com and include the output of the Java Console in the issue description.

But I had Java installed before.  Why did it stop working?

By default, Firefox periodically checks with a server that maintains a "block list" of versions of browser plugins with known/reported security vulnerabilities.  When one of the installed plugins is found on this list, Firefox will automatically disable the vulnerable plugin.  Mozilla has never block-listed a version of Java that did not have a newer version available that fixes the vulnerability.  So this is way to force you to keep your plugin updated to the safest version.

In the case of a machine that is dedicated to running QLess Monitor or QLess Kiosk, and is not used to navigate to any non-QLess websites, it is safe to disable the blocklist feature, and prevent Firefox from disabling unsafe versions of the plugin.  To do this, navigate to "about:config" in Firefox, enter "extensions.blocklist.enabled" in the search field, and double-click the result to change it from true to false.  Note that this is only a safe configuration setting on a machine that is dedicated to running QLess Monitor or QLess Kiosk, and that is not used to navigate to any non-QLess websites or to run any other programs.