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MS Exchange 2010 Outook Web App "Untrusted Connection" error in Firefox. No issue with IE or Chrome


I installed Microsoft Root CA Certificate on my Computer. (For Exchange 2010 Outlook Web Access) But Firefox appear "This Connection is Untrusted" error ((Error code: sec_error_unknown_issuer)). IE and Chrome works fine. My firefox version is 18.0.1.

I want to fix this issue without adding a exception. Please help.

Additional System Details

Installed Plug-ins

  • Shockwave Flash 11.5 r502
  • Next Generation Java Plug-in 10.10.2 for Mozilla browsers
  • NPRuntime Script Plug-in Library for Java(TM) Deploy
  • Google Update
  • The plugin allows you to have a better experience with Microsoft SharePoint
  • Microsoft Lync 2010 Meeting Join Plug-in
  • VLC media player Web Plugin 2.0.2
  • 5.1.10411.0
  • Adobe PDF Plug-In For Firefox and Netscape 10.0.0
  • The plug-in allows you to open and edit files using Microsoft Office applications
  • Office Authorization plug-in for NPAPI browsers


  • User Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:18.0) Gecko/20100101 Firefox/18.0

More Information

  • Top 10 Contributor
  • Moderator
10753 solutions 96760 answers

Try to export those certificates in IE and import the certificates in Firefox.

  • Tools > Options > Advanced : Encryption: Certificates - View Certificates

If this is to be a root certificate then you need to set the applicable trust bits.