I have had my Hotmail account set up on my iphone for a while and suddenly tonight I cannot send emails from my phone.  When I try I receive a message that says "Cannot Send Mail, An error occurred while delivering this message."  I have tried, restarting my phone, deleting the Hotmail account off of my phone and adding it back (with restart again) to no success.  I have a separate email account on my phone and can send and receive emails just fine from it.  I logged into my Hotmail account from my laptop and was able to use it without any difficulty.  Any suggestions would be greatly appreciated.

Many thanks.