AFR for T1 2021 will be part of the ProFile 2021.3.0 release, available for download the week of February 14, 2022, (next week, middle of the week). ProFile 2021.3.0 contains the Efile enabled 2021 version of the T1 2021 module.
I don't think this error has anything to do with Profile. I did one CRA auto-fill yesterday and got the same error. One minute later I tried again and managed to auto-fill without any problems.