Most of the time, when you are experiencing problems to sign in to your Hotmail account, you will receive a very specific error message that explains the cause of the problem, and give you some helpful pointers and troubleshooting tips. In one case, however, Windows Live Hotmail will just give you a generic "Sign-in Error" message before even showing you the login screen. While there can be variants on the actual sign in error message you get from Hotmail, here is the generic one, which we'll explain in this tutorial: "Windows Live Hotmail was not able to sign in to your account at this time. Please try again later".
You can receive this error message either after you go through Hotmail sign in (i.e., manually login to your Hotmail account) - or simply when you load your emails by typing www.live.com or www.hotmail.com in your web browser's address bar (or by clicking on a bookmark / Internet Explorer favorite), when you are set to automatically sign in to Hotmail for this particular browser. The fact that you get the same sign in error is normal, since both scenarios achieve the same end, to try to login to your email account, using the credentials you supplied (Windows Live ID as user name, and your password).
You may see a "Help" link displayed below the error message, which is a generic explanation which we reproduced and explained here: Windows Live help on Hotmail Sign-in Error. Briefly, it explains that the most common cause of receiving the Hotmail Sign in error message and other problems relating to the login process (with sample error messages you may also get), is most likely tied to Hotmail's servers. They go on to explain that you can try to optimize your web browser (Internet Explorer, in that case) for Hotmail access, by performing a few somewhat complicated tweaks.
In our experience, there are two simple ways to fix this problem:
Tip: keep in mind that when you receive the generic "Hotmail Sign-in Error" described in this tutorial, it will 99% of the time be a problem with Microsoft's mail servers themselves, and nothing on your web browser or computer. So don't go crazy tweaking your browser settings, which could create other problems without fixing this one! (Especially if you were previously able to login to Hotmail from it.)