Are you using a VPN client when you get this error? I see various references to configuration glitches with Juniper products such as a possible oversight in configuring the Web ACL.

(What I just said is like a foreign language to me, but maybe it means something to your IT if you're using a VPN.)

It is a little foreign language, but I looked it up, and no I am not using a VPN. It is a personal connection at my home directly connected to a DSL Router.

the blocked site is juniper though.

One possible reason a site might not recognize you as an authorized use is if cookies are blocked. They can be blocked by settings in Firefox or by add-ons or possibly by external security software. This article has suggestions on where to check for Firefox settings issues: Websites say cookies are blocked - Unblock them.

Also, have you tested other browsers (e.g., IE 11) on your home computer to see whether those work any better?

Boot the computer in Windows Safe mode with network support (press F8 on the boot screen) as a test to see if that helps.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/

Do a malware check with several malware scanning programs on the Windows computer. Please scan with all programs because each program detects different malware. All these programs have free versions.

Make sure that you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  http://www.malwarebytes.org/mbam.php
• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  http://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender:
  http://windows.microsoft.com/en-us/windows/using-defender
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  http://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• Anti-rootkit utility TDSSKiller:
  http://support.kaspersky.com/5350?el=88446

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked
• https://support.mozilla.org/kb/troubleshoot-firefox-issues-caused-malware