What causes this issue?

The capitalization date &V2& is not in the validity period from &V3& to
&V4& for investment support key &V1&.

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?

a. You have used the wrong investment key. Correct this.
b. The investment key &V1& is correct.
Confirm this by pressing ENTER.
b.1 Check the definition of the validity period for the investment key
&V1& and correct it if necessary.
or
b.2 Enter an capitalization date &V2& within the validity period from
&V3& to &V4&.

Error message extract from SAP system. Copyright SAP SE.