When registering with HMRC for a username and password, it can take 7 to 10 working days to receive it.
If you try any payroll submissions within this period, they will fail. You can still run your pay run so you can give your employee’s their payslips. It means you will need to put in a dummy username and password as a temporary measure.
Doing this will mean your submission to HMRC will fail. As soon as you receive your username and password you can resubmit and select a late reason.