Hi, I am sorry that it did not work for you. It worked for me but that seems to be the case for some of the other recommended solutions. I also got locked out trying some of the recommended solutions.
I phoned the CRA and the service was excellent - took about 30 minutes on the wait list to get in which was quite acceptable to me. The CRA rep unlocked the account and was very helpful and wanting to know about the issue. He looked at the error messages that showed up on his system. After unlocking, he helpfully encouraged to try it again to make that it worked so I submitted my T1135 and got confirmation. The other solutions I tried did not work and then he reset the account again so I had a full 5 tries again.
The idea I mentioned worked on the first try. If there was any difference, then can correct through amendments later but at least the first filing to get a refund faster by net filing worked.
