Enter start of term for American-style exercising of option (&1)

What causes this issue?

For options with American exercise category, the start of the term is
the same as the notification period.
The start of the notification period is required for the analysis of the
generic transaction. However, this value is missing from elementary
transaction &V1&.
<ZH>Note:</> The system determines the number of the elementary
transaction for a generic transaction (transaction RCA00) by assigning
numbers, starting with 1, on each level of the hierarchy tree, starting
from the top and working downwards. In the external data transfer, this
number matches the NGIDNR, the sequential number for a GID in the FGET.
<ZH>Example:</>
Number,, Tree
1,,,, Elementary transaction (top level)
2,, ,, |_ Elementary transaction (second level)
4,,,, |_Elementary transaction (third level)
5,,,, |_Elementary transaction (third level)
7,,,, |_Elementary transaction (fourth level)
3,,,, |_ Elementary transaction (second level)
6,,,, |_Elementary transaction (third level)

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?

Enter the start date of the term.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.