No reference period(s) selected

What causes this issue?

Several different intervals were defined for the reference cost center.
To use this cost center as a reference, you must select one interval as
a reference in order to continue processing.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Use one of the invervals as a reference, or change the reference cost
center.

Error message extract from SAP system. Copyright SAP SE.