Sometimes you may see error code 121 when trying to efile a return. It basically means the password for your efiler ID during the transmission does't match CRA records. It could happen if the password you set up in the software is not correct, including typos. Another common case is that you forget to update the password in the software after you renew your efile ID and password each year.
- Anyway, in this situation, please first verify your password setting in the software. You can consult this FAQ if you don't remember where to set up the password: How to change EFiler ID and password. After the password is corrected/udpated, please save the return file one more time to ensure the change is reflected, then efile again.
- If you still get the error 121, don't try to efile again as you account may get locked after 5 unsuccessful attempts. Please call CRA Efile helpdesk to verify if you have the correct password on hand. Please repeat step 1 with the new password.