The government gateway is busy or not available
IRIS Payroll Basics
The government gateway is busy
A message tells you the submission has been received and awaiting further processing.
This means the HMRC have your submission, but its in a queue. The software is not able to record it as successful as it may fail once it is processes. You receive an email notification with the status of the submission.
The government gateway is not available
Unfortunately, all we can do is wait and try again later. Keep a note of the date and time. Support are unable to provide any further advice.