Problem
535 5.7.139 Authentication unsuccessful, federated sts service was unreachable error message presented by Jira after integrating Microsoft 365 with Duo Single Sign-On.
Cause
Jira version that was used did not support modern authentication which was configured on Duo.
Solution
Upgrade Jira to a version that supports modern authentication
or
Configure the Microsoft 365 application within the Duo Admin Panel to enable the ‘WS-Trust’ feature
Supporting Documentation
What are the impacts of enabling modern authentication on the Microsoft 365 tenant