KB-1854 Opening a User constant throws an "All users and groups must be valid and visible to the viewer" error

Symptom

When attempting to open a constant containing Users, the constant fails to open with the following error message:

The System Has Encountered an Error
HTTP Code: 500
APNX-1-4198-000

Error Evaluating UI Expression
Expression evaluation error : Error in a!forEach() expression during iteration 1: Expression evaluation error at function a!aos_overrideEditLink [line 9]: A user and group picker component [label=""] has an invalid value for "value". All users and groups must be valid and visible to the viewer.

Cause

One or more of the users contained in the constant were renamed, and thus Appian does not recognize the old username present in the constant as a valid username.

Action

Re-import the constant from another environment and configure it to contain the correct users with new usernames. If the constant cannot be imported from a lower environment, recreate it.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: January 2019