KB-2153 Users see "Unexpected token < in JSON at position 0" error


Users that authenticate with SAML see the following error when navigating around Appian or interacting with an interface:

The error may also appear if one or more of the following apply:

  • The session timeout in Appian and the session timeout in the Identify Provider have different values.
  • Users are inactive in Appian for a prolonged period of time.
  • Users log out of Appian in one tab while still having Appian open in a second tab. When navigating around the second tab, they see this error.


This often occurs when the Appian session has timed out, and the user interacts with a SAIL interface. This issue has been hotfixed via AN-87093 in Appian 20.4 and later.


Upgrade to Appian 20.4 or later.

Affected Versions

This article applies to Appian 20.3 and earlier.

Last Reviewed: November 2021