Hello wilgat82,
There is a feature by which sellers can block buyers who are registered in countries to which they don't ship. This could be the warning message you are seeing. Please note that this feature looks at the country of registration, and not Shipping Address.
You could contact the seller and ask him to remove you from his 'Blocked Bidders' list.
Hope this answers your queries.
Thanks and Regards,
Rohit,
Community Development Team
Thanks and Regards,
Rohit,
Buyer Engagement Team