A difference can only be posted for period & &

What causes this issue?

The first count was posted for this physical inventory document in the
period &V1& &V2&. The differences must likewise be posted 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?

Change the posting date so that the differences can be posted in
posting period &V1& &V2&.

Error message extract from SAP system. Copyright SAP SE.