Only 1 or 7 is valid for cycle length

What causes this issue?

You attempted to enter a cycle length other than one day or seven days.
However, this is not a valid entry.

How to fix this error?

Enter a cycle length of one day or seven days.

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

Using the predefined cycle lengths makes it easier for you to determine
which day of the cycle, (for example, which shift definition) is valid
on a certain day within the available capacity interval.

Error message extract from SAP system. Copyright SAP SE.