Error 7806: This submission cannot be accepted

IRIS GP Payroll

There are a number of potential reasons :

HMRC aren't expecting this employer filing RTI returns until a later date

Contact HMRC Employer Helpline on 0300 200 3200 and ask them to set your RTI start date to the correct date.

Payroll Agent not authorised to file on behalf of this client

If you act as a tax agent or adviser, you must have formal authorisation to deal with HMRC on your client’s behalf.
It’s easiest to do this online using HMRC Online Services.