Did you receive the following error (or something similar) when trying to close the books?
you can’t close the books with qoh less than zero
This occurs because an inventory item can’t have a quantity on hand that is less than zero on the date you specified to close the books. […]
Resolution for 'closing the books issue: 'Error when closing the books' available: Yes.
The closing the books issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the closing the books issue yourself by looking for a resolution described in the article. If it is a complex closing the books issue or you are unable to solve the issue, you may contact us by clicking here or by using other closing the books support options.
For more information about resolving issues related to closing the books in Quickbooks/QBO or to get support for the issue 'Error when closing the books', click the link below: