<Errors xmlns="http://schema.intuit.com/platform/common/error/v1"> <error> <code>AuthenticationFailed</code> <type>INPUT</type> </error> </Errors

Hello ajbimprovements, 

Welcome to the Community page, 

How is it we can help you today? What are you trying to do when you get this error in Quickbooks?

Could you please provide us with more information on what it is your doing in Quickbooks so we can help resolve your issue thanks.