Office 365 – ADFS authentication error code 8004789A when logging with web browser

If you are using Office 365 and have implemented ADFS to manage the authentication to Office 365 services, this post is for you Smile

You may get the following error code – 8004789A – when logging on to Office 365 with web browser (Exchange Online OWA or SharePoint Online), while Outlook or any ActiveSync device is working fine


The solution is simple:

check if the Issuer (URI) URL is set to HTTPS; if the answer is yes, you have to change the configuration to use HTTP only

run the following command from a PowerShell window on the ADFS server

Add-PSSnapin Microsoft.Adfs.PowerShell
Set-ADFSProperties -Identifier "http://<your ADFS URL>/adfs/services/trust"
Restart-Service adfssrv

Also on the TMG side, check if the following settings are correctly set:

  • Apply link translation to this rule – available on the rule property below the Link Translation tab – is disabled


  • Verify normalization – available on the HTTP policy property – is disabled


Leave a Comment

Your email address will not be published. Required fields are marked *