Hi, what happens when you try to sign in to your Microsoft Account? For example: * The site displays an error message -- what is the message? * The site cycles back to the login form without explanation * The site goes back to Bing but you aren't logged in on Bing * Something else? ---- ''If this problem just started recently:'' Firefox recently rolled out "Total Cookie Protection" to more users. This limits how sites can use "third party" cookies, meaning cookies from different websites than the one you see in the address bar. If Metro or T-Mobile shuffles you between multiple different servers (you see very different web addresses during login) then you might not get logged in on all of the related sites. You can make exceptions to this feature when needed. More info in the following articles: * [[Introducing Total Cookie Protection in Standard Mode]] * [[Total Cookie Protection and website breakage FAQ]]