Why cann’t messages be sent by Hotmail?

Sometimes when I try to sent emails I get messages such as :

        Unable to send or receive messages for the Hotmail (henryjdarrell) account.

        Subject 'Fw: update'
        Windows Live Mail Error ID: 0x80048820

        Unable to send or receive messages for the Hotmail (sdarrellag) account.

        Subject 'Explanation of non-competivie eligiblity, age discrimiation'
       Windows Live Mail Error ID: 0x8DE20007

What do these error messages mean?  Why can't messages be sent or received?

I use a HP  G62-43OUS Notebook with Windows 10 and an IBM Thinkpad T42 with Windows XP Professional.

Any help would be appreciated,

henry