Windows Live error - Server Error:0x80048820

I have a client that uses MSN and than one day they were unable to send or receive Email with Windows Live.

Unable to send or receive messages for the Msn (xxxxx) account. Sorry, we were unable to sign you in to Windows Live ID at this time. Please try again later.

 Server Error: 0x80048820
Server: 'http://mail.services.live.com/DeltaSync_v2.0.0/Sync.aspx'
Windows Live Mail Error ID: 0x80048820

They did get it resolved and here are the steps we took

1) Checked the date & time on the computer

(they were fine)

2) Open Internet Explorer

Go to TOOLS

Go to INTERNET OPTIONS

Go to the ADVANCED tab

Scroll down to the SECURITY heading

Uncheck "Check for server certificate revocation*"

Click Apply

Click OK

CLOSE INTERNET EXPLORER .....

(still did not work)

3) Changed server options for hotmail account from HTTP to POP3

(still did not work)

4) (The fourth time was a charm and here is what resolved it for them)

It was the 'invalid character' in my first name of my Windows Live ID. 
I went to http://account.live.com/
signed in to the affected account
selected the 'Registered Information' link
Selected 'Change' next to my name
changed the '&' in my name to 'and'
saved changes

All working OK in my Windows Live Mail now. 

updated 03-22-2010