Error 3001: Document has failed due to departmental specific logic in the body tag
IRIS 12Pay
This is a generic message generated by HMRC indicating ONLY that the submission has been rejected.
These types of errors usually occur when a field in your submission has an invalid data entry, ie. text in a number field, the wrong number of decimal places, an incorrect date format. They can also be caused by account issues with HMRC gateway service.
Usually, when a submission is rejected by HMRC with a 3001 error it is accompanied with further information about which data field their system has a problem with. This should tell you why the submission has been rejected, however, some of these messages can be difficult to interpret.
Here we have an example of an FPS rejected with error 3001. Accompanying this is the reason why it was rejected; error 7806. In this case, the problem was caused when the payroll agent making the submission had not been authorised by the client with HRMC.