Same here, every time I access the page I have to log in again regardless of what browser or device I use. And the login always results in an "invalid redirect" message, although it does successfully log me in.
I don't stay logged in but I figured out what has been causing the invalid redirect message. It always pops-up when my browser hasn't fully loaded the page....especially the advertisements. When I'm a little more patient and let it fully load before I try and log in, I've had no issue.