We are aware that some users are encountering the following error message when attempting to file slips: “Filer account number is missing or invalid for this type of return.”
If you receive this message, it likely means that the filer account number you are using has not been registered to file the slip type you are attempting to file. Note that the filer account number is the issuer Account number entered on the Info worksheet. 
You will need to contact the Canada Revenue Agency (CRA) to register the filer account number. You can call the CRA directly at 1-800-959-5525 to obtain help registering the filer account number.
You may also register a filer account number to file slip types using the CRA’s Represent a Client portal if you have the required level of authorization as indicated on the page.
Read the CRA’s page on Electronic filing only by using Web Forms or Internet file transfer (XML) to learn more about electronic filing of slips.
