The status of the STP double-click Event when you receive this error will be 'Failed Validation: Gateway Error'.
When you double-click on the Pay Event or View Details, you will see the error in the Status column of one or more employees.
To fix this issue, after you have identified the employee:
Go to Payroll, Maintenance, Employees, Employees and Edit the employee.
In Personal Details, click into the email address field and delete any spaces at the end.
Click OK to save the record
You can now submit an STP Update Event for the Payroll Company.
If the error doesn't appear next to any of your employees, you should review the company details in the two locations below:
Payroll, Maintenance, General, Payroll Companies
Common, Maintenance, Company Details
If this does not solve your issue, raise a case online and reference the title of this article. Include the Period End Date and employee(s) affected in the description.