Here are the steps to reproduce this issue:
1. In PPM, create an AC to PPM integration with Agile Central, providing the Workspace, Project and Owner
2. Create a project in PPM and link it to the integration created above
3. Run the Synchronize Agile Central job (Rally Synchronization job)
4. In Agile Central, add more than 20 milestones to the project used for the integration
5. Still in Agile Central, create 3 or 4 features to the initiative created for the PPM project
6. Add all milestones (more than 20) to the features (divide them by each feature)
7. Run the Synchronize Agile Central job again
Expected Result: Features are created with the respective milestones and job completes.
Job fails with the following error because not all milestones are loaded from Agile Central:
API-1019 : Could not process the request due to internal error.
CA PPM version 15.2 and 15.3.
This is caused due to a defect, DE36575.
Defect DE36575 has been fixed in 15.4. It has also been fixed in 15.3 (Patch 1).