The user is receiving the following error message whenever he or she presses the "Return" or "Save and Return" buttons from the Non-Labor Cost Plan page:
ERROR 501 - NOT IMPLEMENTED and the server does not support this feature.
CA PPM 15.1+ On Premise and SaaS
The application is building the return_to URL incorrectly. The return_to URL points to a page that does not actually exist so this error is displayed in the UI.
We are not able to consistently reproduce this issue in our labs (i.e. there is no consistent STR for reproduction), so our Sustaining Engineering team is not able to fix the defect.
Please contact CA Support and point them to this article. The resolution requires some analysis of the PPM DB records and updates to the same.