Getting an error message on login to one of my shaw webmail accounts. The curious thing is that if I intentionally put a wrong password in, I get the correct response from the server "incorrect password". However, if I put the correct password in I get the 400 error.
I went into the admin panel and changed my pw just to be 100% certain things were correct. I still got the same result.
I think this is trouble on your end as I see this issue from several other people.