Our company is unable to log into a particular Office Add-in using ADFS SSO. The SSO does not appear to “hook” correctly and instead redirects to a blank page. This issue only occurs in Outlook 365 for Windows. We tested this on both managed and unmanaged machines as well as on and off prem. Outlook 365 for Mac and Outlook 2019 Professional Plus for Windows both work fine.
We examined our firewall and ADFS logs but nothing appears to be blocked. We also checked Office 365 admin center to see if there were security settings preventing Office Add-ins from working correctly but did not find any.
We troubleshooted with the developers of the Add-In but they have not been able to identify the cause of this issue. At this point we are scratching our heads. Is this a programming issue or something else?
Thanks in advance!