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.
Jira version that was used did not support modern authentication which was configured on Duo.
Upgrade Jira to a version that supports modern authentication
Configure the Microsoft 365 application within the Duo Admin Panel to enable the ‘WS-Trust’ feature
What are the impacts of enabling modern authentication on the Microsoft 365 tenant
How do I enable and properly secure basic authentication for Microsoft 365 when federating with Duo SSO