New email addresses

Hi

I've added 2 alternative email addresses to my account for email publishing but each time I send an email from either address I get this:

You do not have permissions to create content beneath the item.

Please check the following:
1. You have been granted create permissions on the item.
2. The email address you are sending the content from is registered with your Sosius account. If it is not, then add it as an alternative email address on your account.

What am I doing wrong?

Thanks

Elliot