If your email address TLD has more than 4 characters, you can't sign into Public Mobile any more. They switched to "EverSafe", Telus' auth provider, a month ago.
I'm currently going back and forth with support over it. For which I had to create a second account to even access the community website.
Try it yourself! visit https://myaccount.publicmobile.ca and enter any TLD with 5 or more characters to see the error message.
