Key date is unknown

What causes this issue?

The key date on which the data for the compliance check is to be read,
is unknown.

System Response

The system terminates the compliance check because the result of the
check can depend on the key date and therefore, the result cannot be
clearly determined.

How to fix this error?

Contact your system administrator.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.