Posting has already been performed in the last posting period &

What causes this issue?

Posting has already been performed to the last posting period &V1& in
fiscal year &V2&. You can only perform repeat runs in this 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?

Check your entries. Since postings have been made to the last posting
period, you can either perform a repeat run in this period, or post to
a new fiscal year.

Error message extract from SAP system. Copyright SAP SE.