Generally, this error occurs while performing operations with QB-POS.
So you need to follow the mentioned steps;
You need to re-establish the POS connection with Webgility. In Webgility Desktop, navigate to Integration > Accounting/POS/ERP > Edit Connection.
2. Make sure you have entered the correct POS data file name, POS server name, and POS version, and click Connect to QuickBooks.
3. If you still receive the same error message then you need to update Webgility to the latest version.
Follow the steps mentioned in the following help article to update the software How to Update Your Webgility Desktop Software.
4. Once done, try posting orders again.
Initiate a Support chat if the issue persists.