&1: &2, correction: &3

What causes this issue?

The identifier you have entered is invalid. The check function has
therefore corrected the identifier accordingly.

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?

Choose ENTER, to confirm the correction. The system adopts the
corrected identifier.

Error message extract from SAP system. Copyright SAP SE.