This error displays when there is an issue with the project hierarchy or the way the phase is being created.
Common reasons include:
- Duplicate ID: The phase ID you are trying to use is already in use by another project or phase in CORE. All project and phase IDs must be unique.
- Hierarchy changes: You are trying to change a project–phase hierarchy incorrectly. For example, if you want to flip a phase and its parent project, you must first unlink the phase to make it a standalone project, and then reassign the parent relationship.
- Depth limitation: CORE supports only 4 levels of phases. Attempting to create a phase beyond this limit will trigger this error.
- Invalid parent assignment: An active phase cannot be assigned to a parent project if the hierarchy steps are not followed correctly.