Period &1 is not valid

What causes this issue?

Posting period &V1& does not agree with the posting period determined
by the system.
From the posting date &V2&, the system determined period &V3& in fiscal
year &V4&.

System Response

Since posting period &V1& is not valid, the posting cannot be carried
out.

How to fix this error?

Either specify a posting period that agrees with posting date &V2& or
make no entry for the period. The system then derives the correct
period from the posting date. If the posting date lies in the last
posting period of the fiscal year, specifying a special period is also
permitted.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.