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SSO Authentication failure - ADFS keeps on prompting for credentials

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I'm having a problem with my ADFS implementation :

When I attempt to connect to Office 365 (through using a federated user the browser keeps on prompting for my credentials even though I've correctly filled in the fields.

  • I have installed ADFS on  my server and configured the trust
  • My IIS server is enabled, I have applied my certificate onto the default website, the binding has been set up correctly
  • I have installed on my 2nd server the dirsync tool, which works fine
  • My domain has been correctly federated through PowerShell
  • My DNS records are correct (expect for the Lync Online part)

I don't have any error message in my Event Viewer

Thanks for your help !

All Replies
  • Hello

    I had this problem and the cause was that the internal DNS had a CNAME instead of an A record pointing to the name of the federation service. After changing it to A, SSO started working immdiately and the 401.2 errors disappeared.


  • Strange I´m using a CNAME internally to point to the ADFS server and I have no problems with SSO.

  • I was told by Office 365 support that ADFS and IIS were "out of scope" for them...

  • hi,

    what key did you change in registry and what brought you to that change, please ?


  • he added a DWORD value DisableLoopbackCheck (as data entered 1)  to key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa