SOLVED Cannot login - redirects back to login page - no errors

[JAKE]

have you set your root url to http://localhost/gs in the settings page?

U mean the "Website url" field? Yes, it matches and I've tried it with and without trailing slash.

I can confirm that I can login with all other browsers IE, Opera, Chrome and even Tor.

But seems like the solution was to use IP address instead of hostname since http://127.0.0.1/gs/admin/ fixed this problem.