Why is Windows Live Hotmail rejecting email I send to my friend?

I can Imagine that thing also this unsuccessfull Email result can be get by alot of hotmail users. so what should we have to do?

As far as i can understand this problem can be happen because simply window live hotmail things that you are a spammer. A spammer is a person who sent millions of emails to others without any need of the specific person. And if we want to know this from hotmail authority then simply they can't tell us.

• Because hotmail thinks we are a spammer.
• At the time of sending mails internet connectivity is fail.
• Windows Live Hotmail service has unknown error.
• May be because you are using Dynamic IP and the person who used that previous IP address sent a lot of emails from his windows live Hotmail account.
• Your Computer is infected by the virus which is used now a days to send a lot of emails from windows live account owner.
• You are not a spammer but the other user of windows live hotmail account owner thinks that you are sending email to them which making them annoy.

• Don't send a lot of email in a day from your windows live hotmail account.
• Don't sent email to those hotmail account owner who takes your email as "JUNK"
• Use good antivirus to protect your computer from spyware, malware and virus.
• If still getting same error then call your ISP Provider for technical assitance.