If you are a tax preparer or EFILE user and are seeing CRA response code T837 – Rejected when submitting a return, you are not alone. This error has become increasingly common due to recent CRA process changes around Authorization for a Representative (AUT-01 / AUT-REP).
Due to recent CRA changes, Authorization for a Representative can no longer be submitted through EFILE as part of the tax return submission.
Even if:
You received a newly signed authorization form from the client
The client re-signed the authorization
You requested a fresh authorization
The CRA will still reject the submission if the authorization is being sent through EFILE.
This is why you may see:
The old authorization still showing
The new authorization not updating
Repeated T837 errors even after redoing the form
What You Need to Do Instead
CRA now requires Authorization for a Representative to be completed outside of EFILE, using one of the methods below.
Option 1: Client Uses CRA My Account (Recommended)
The client can:
Log in to their CRA My Account
Go to Manage authorized representatives
Add the EFILE preparer’s RepID directly
This is the fastest and most reliable option.
Option 2: Submit Through CRA Represent a Client
The authorization can also be submitted through:
CRA Represent a Client portal
Once CRA processes it, the authorization will appear correctly on their end.