FAQ: QuickBooks Desktop: No Vendor Found For Email in QuickBooks
Each submitter’s email must be saved as the "Main Email" in their Vendor record within QuickBooks Desktop.
To resolve, click into your vendor section of QuickBooks. Next, make sure that the email mentioned in the error matches the "Main Email" field in their record. This is case sensitive, so you will need to change any capitalized letters to be lowercase.
Once you have added the correct email to the vendor record, save this change and sync your policy before trying to export this report again.