Also enter the absence for the first day of the next duty alloc. period

What causes this issue?

You have entered an absence on the last day of the duty allocation
period.

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?

Since absences need to be entered for each individual calendar day and
the current duty allocation period ends before 24:00, also enter the
same absence for the remaining day of absence on the first day of the
next duty allocation period.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.