Check entered data across all modules where occur movements of items to the Goods module by using automatic posting summary report. You can also check posts in the Cash Transactions module. Usually, errors occur due to subsequent modifications made in the Document Types settings, Items register. In addition, by changing the account settings or manually modifying document and date values which is not followed by posting, though...
Example:
You purchased 10 pieces of item 1 in March. You receive an invoice from supplier and post it accordingly.

Subsequently you find that due to transport expenses you have to increase cost of item 1. Proceed by entering cost in the
Costing panel and confirm it. Thus increasing stock value that is shown on the warehouse card. To modify the amount of inventory posted, you have to re-post the document, but you forget to do it.
To find out whether an error occurred when posting document type 100 at the end of the month, just check the automatic posting summary report. Select the criteria and click Select. Documents whivh were posted incorrectly (or those unposted) are displayed in the errors list. It can be observed that there is also the Alpha Trade's invoice among them. Here you changed the item's inventory value but you did not change the amount posted.

An error has occurred with your document 5029 - Posted value does not match document!. Rremove the error by automatically reposting the invoice.