If the problem persists, this may be the result of a known issue. Some users have reported similar behavior in their accounts. The engineers are aware of this problem and are working diligently to get it resolved. You may want to give the support team a call to be added to the list of affected companies. Once you're added to the list, you'll receive email notifications regarding the status and resolution for the autofill problem. The number to speak with an agent is 1-800-488-7330. The most up-to-date contact information can be found here: https://help.quickbooks.intuit.com/en_US/contact. You can advise the agent that this is most likely related to investigation #14518.
One way to workaround this function not working would be to type the information in the desired field. This is a temporary fix and you'll be able to use autofill again soon.
I wish you and your business continued success. I'll be here if you have any other questions.