Some of you who tried to login to Google Webmaster Tools over the weekend may have been out of luck. There were many reports of login errors for the Webmaster Tools system.
Those reports claimed Google was returning an error, "too many redirects."
Google confirmed the bug and said:
A small subset of users are seeing a "too many redirects" error when attempting to access Google Webmaster Tools. We are aware of this issue and are looking into it. In the meantime, you can access Webmaster Tools directly though the URL https://www.google.com/webmasters/tools . Thank you for your patience.
I am not sure if it is fully resolved yet but if you are having issues and must access Google Webmaster Tools, use https://www.google.com/webmasters/tools instead.