well here is the problem I am trying to send an email to one email adress and they just can't get it from me The email adress is a xxxxxxx@their website domain What could be the problem? And yes it worked before.
They've enabled a spam filter via their cpanel, e.g. boxtrapper, spamassassin and they haven't whitelisted you?
you are blocked by them so you can't get through Try with some different email id and from different IP too