No Payslip found for Employee/Period
To upload payslip adjustments a payslip must already exist in Xero. UpSheets will upload the data to the draft pay run for the employees pay calendar.
To resolve this error, simply create a pay run in Xero and revalidate your file.
If using an unscheduled pay run, be sure to open the pay run and select the employees you wish to upload data for as payslips are not automatically created for employees on unscheduled pay runs.