If a user takes one minute or more between a request form loading and when the user submits the form data, the user receives an error and is redirected to the Identity Provider (IDP) for authentication.
The Service Provider was honoring the Session Duration value sent in the assertion by the IDP. This value defaults to 60 seconds in Single Sign On.
Release: MSPSSO99000-12.8-Single Sign-On-for Business Users-MSP
Increase the IDP's Session Duration value to the maximum session time the Service Provider wants to allow before re-authentication.