The QuickBooks Web Connector (QBWC) only allows one (1) instance of the same application to be connected to the same company file. The QBWC 1039 error can occur if your vendor is configured to connect with QuickBooks through the Web Connector on two (2) different instances of the same company file.
Right-click on the .QWC file and select Open With.
Expand Other Programs in the Open With window.
Select Notepad and click OK to open the .QWC file in Notepad.
Select Format > Word Wrap to fit the text to the window.
Change a single (1) character in the OwnerID string and a single (1) character in the FileID string.
Note: You can change any of the 0-9/A-F characters to any other character in the range 0-9/A-F. It doesn't matter which character you change, but keep the case consistent. If the rest of the characters are lowercase, make it lowercase. if the rest of the characters are uppercase, make your new character uppercase.
- Select File > Save.
- Re-load the modified .QWC file into QuickBooks Web Connector.