I have the same issue. It is the first year of business with the start of the business year in Sept 2022 and the end in Aug 2023. I tried changing the business year end to Dec 2022 but that did not solve the issue. A T4A was issued to me for fees. However the payment was really an honorarium as there was no agreement concerning the fees.
There are no warning or errors during the Review of the return but Netfile attempts result in the 49-S error.
Is there any way of determining what omission is causing the error?
Is the only alternative to mail in a paper copy of the return?
