I recently updated my Incredimail program - I use Hotmail for my emails. After the update I found that the program was not receiving any emails, I eventually discovered that Hotmail had changed their Server address in Incredimail. I changed my Server details back to they were before the IM update and since doing so everything is working properly.
It appears to be a Hotmail problem which is being 'worked upon' at this moment.
Check your Server details to see if yours have been changed.