Hi.
I can see that the community has been asking you for years why they can't sign in using their usual method for autofill. The provincial sign-in partner is not available, which is how I have signed in to my CRA account for many years. I don't have a MyCRA login and making one requires me to wait weeks for a security code to be mailed to me.
I'm signed in on the next tab using my provincial sign in, all of my data is available, and all Autofill would have to do is give me access to my usual sign in method. Why do I have to create a new CRA account? Why can't I sign in using the secure method accepted by the CRA?