have you checked the log for batch determination? It usually has some info why a batch is not selected.
Further you should always post an error message 1:1 instead of interpreting an error message
Not to forget that you need to search SCN before posting, as this case with "Deficit of stock with Batch no" is discussed probably a hundred times before.
But this message just come up because you wanted to overrule SAP by entering the batch which was not found automatically. So instead of focusing on this follow on error you should analyze the root cause, the batch determination itself, to find out why the batch could not be picked automatically