Step 1 : System Options - General - Account code - Format is xxxxxxxx and they didn't tick the column of 'Free Text Format for Account code'. Step 2 : File - General Maintenance - Default Interface Account - Prompt message 'Invalid Account Code.' 


To solve this problem, have to go to QnE Management Tools - Tools - Intelligence SQL Queries - tick the column of 'Overwrite General SQL', key in the script as below in the rectangle column then click on Execute SQL icon.

update defaultinterfaceaccount set glaccountcode =''