API Error enabling sub-object of Cost Plan

Products

• Clarity PPM SaaS
• Clarity PPM On Premise

Issue/Introduction

I am trying to API enable a sub-object of the Cost Plan object so that I can use it in the Modern UI / New User Experience and get error:

ODF-0248: Cannot API enable custom sub-object.

Environment

Release : All Supported

Component : CA PPM SAAS STUDIO

Cause

This is working as designed. Sub objects of cost plans are currently not available for API Enablement. 

Resolution

The following subobject types are available for API Enabling as referenced at: API Enable Custom Objects and Custom Investments

Custom Subobjects: You can API enable a custom subobject if it belongs to a

• Project or investment (or supported abstract objects)
• API enabled custom master object