KB-1303 Generic error thrown when trying to create a Quick App

Symptoms

Upon creating a new Quick App, the following error appears:

Quick App Not Created

Oops! Something went wrong and we couldn't create your Quick App. Nothing has currently been created. You can try to create your Quick App again, but if it continues failing please contact a system administrator.

Upon receiving that error, the following error is printed in the application-server.log:

ERROR com.appiancorp.object.quickapps.QuickAppObjectType - Failed to successfully create Quick App on operation 'create rules folder' - rolling back
com.appiancorp.suiteapi.common.exceptions.AppianException: Appian object error. Details: Problem creating Quick App content object by name: T Rules and Constants (APNX-1-4300-000)
...
Caused by: com.appiancorp.suiteapi.content.exceptions.InvalidContentException: Invalid Content ID
ERROR com.appiancorp.object.quickapps.QuickAppObjectType - Failed to create a new quick app
com.appiancorp.suiteapi.common.exceptions.AppianException: Appian object error. Details: Problem creating Quick App content object by name: T Rules and Constants (APNX-1-4300-000)
Caused by: com.appiancorp.suiteapi.content.exceptions.InvalidContentException: Invalid Content ID

Cause

A user deleted all associated objects with a Quick App, including the "Quick Apps Rules and Constants" folder. This folder is a system folder that is created after installing/upgrading to Appian 16.2 or later and is required to create a Quick App.

Action

Restart the application server to have the system recreate the folder.

Affected Versions

This article applies to Appian 16.2 and later.