Posting period was postponed during runtime

What causes this issue?

The current posting period changed while this document was being
entered.

System Response

The posting cannot be carried out because the posting period of the
material master
record differs from the posting period in the current transaction
buffer.

How to fix this error?

Restart the transaction and enter the invoice again.

Procedure for System Administrators

If possible, run the period closing program (transaction MMPV) at a time
when there are few postings in the system. This avoids impairments to
system activities in progress.

Error message extract from SAP system. Copyright SAP SE.