A user may have trouble signing into a Hotmail account because of an incorrect password, a problem on Microsoft's end or a hacked account. It is important to note that Hotmail accounts have now been replaced by Microsoft Live accounts. Also, Microsoft passwords are case sensitive, and the caps lock button being pressed may cause an incorrect password notification.
To check if there is a problem on Microsoft's end, a user can go to the service status portion of the official Outlook.com website. From here, a notification will let the user know if Hotmail and Outlook are working properly. If the service status on the Hotmail account is green, but a user cannot enter into their account, it is likely that they have been hacked. To report a hacked account, a user can recover use of their account by changing their password. However, Microsoft recommends clearing the PC of viruses before attempting a new password.
Microsoft may also block accounts to protect from fraud or abuse. Too many attempts with an incorrect password will cause an account to be blocked. To unblock the account, users can go to live.com and enter their phone number associated with their account. After following the phone prompts, the user will then regain access. If a user has lost their password, they can recover their account with an alternate email address.