Resolving an invalid certificate error when attempting a sync to QuickBooks.

If you're getting an error from QuickBooks referencing an invalid certificate, check out this article.

QuickBooks requires that all Integrated Applications (e.g., Acctivate) must have a valid Digital Certificate.  This certificate is required to allow the application to access the QuickBooks data.  This also allows future access without the QuickBooks Admin in Single-User Mode.

Acctivate uses a digital certificate from Thawte, a third-party Certificate Authority.  Thawte is a very popular certificate issuer with millions of applications and websites secured by their certificates.

If you sync with QuickBooks and find yourself getting the following pop-up in QuickBooks:

Invalid cert

Then it's possible that the Thawte certificate on your computer is missing or invalid. 

If this is the case, then open a ticket with the Acctivate support team. 
The Acctivate support team can provide you with the top-level Thawte Certificate, which can usually be exported from another computer as a DER encoded binary x.509 (.CER) file, then imported to your computer.