In a continued effort to combat Spammers, Microsoft by default has limited locations such as schools the ability to create no more than 3 Microsoft Accounts in a 24 hour period. If you find that you need to register more than 3 Microsoft Accounts in one sitting, especially in a huge classroom environment, please click on this link.
The link above will take you to an online form that needs to be completed. Once Microsoft has received and approved your request, your institution’s IP Address will be “whitelisted”. Whitelisting grants your institution the ability to create unlimited Microsoft Accounts at anytime and removes the 3 Microsoft Account limitation.