Why Did You Receive the Error?
If you receive this warning when trying to process a payroll to Xero, it means one of your employees in Xero are missing a "Pay Calendar".
How Do Your Fix This Error?
To fix this issue, within your Xero account, find the employee file, go to the "Employment" tab and select a "Pay Calendar" from the dropdown menu that matches the pay calendar set in your RosterElf account (eg weekly, fortnightly etc). Once done, you can go back to RosterElf and process the payroll again.