emails being returned

[#1]

I'm trying to inform people in my address book that I've changed my email address but of the ones I've sent so far they're all being returned with the following statement; 
552 4kN01r00232tsU201kN1uW message rejected due to spam or virus. If you believe this is in error please login to your portal or contact your ISP support team.
Therefore how do I contact people in my address book

[#2]

That suggests that our outbound spam filter is being triggered by something in the body of the message you're trying to send. Does the email contain any links? It might even be your new email address that's triggering things.
Try sending one of the emails using Webmail. It should fail in a similar fashion, after which you should be able to save the message to drafts where I can take a look at it.