I find I cannot send email  (live mail} without receiving the following

There was an unexpected error and Windows Live Mail can't sync the messages in your Hotmail account. To sync your messages, in Windows Live Mail, remove your Hotmail account and then add it again. To view messages in your Hotmail account, go to http://hotmail.live.com on the web.

Subject 'No 0870'
Server Error: 4102
Windows Live Mail Error ID: 0x8DE20003

Can some please explain how to do this