Affinity incident
Authentication Issues with Windows Outlook Desktop App
Affinity experienced a minor incident on June 30, 2026 affecting Affinity for Outlook, lasting 22d 22h. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- identified Jun 30, 2026, 04:06 PM UTC
Some users on Windows Outlook Desktop App are unable to complete SSO login to the Affinity Outlook Add-in. This is due to a recent change on Microsoft's end affecting how Outlook on Windows handles authentication redirects. Mac Outlook is unaffected. As a workaround, users can access Affinity via the web application.
- identified Jul 10, 2026, 08:28 PM UTC
We are investigating an update to the Affinity platform that will work around the issue caused by Microsoft's recent change and restore SSO login behavior for Windows Outlook Desktop App users. Mac Outlook and the Affinity web application are unaffected and can be used as a workaround in the interim.
- resolved Jul 23, 2026, 03:03 PM UTC
This issue has been resolved now. Customers who were impacted will need to update their ACS URL to https://login.affinity.co/auth/{subdomain}/sso/saml-callback and set the SSO Callback Style property to "Login host, direct (circa 2026)" to opt in to the fix. The web application and Mac Outlook were unaffected throughout. Customers needing help can contact Affinity support at [email protected].