Users foreign email adres-no email problem : no answer yet

Everybody with a .pl address does not get confirmation emails, newsletter, notifications, pm's, emails.... nothing. And no, they are not in the spam folders, I have checked myself, and yes, they have notifications checked.
But change address to .com or .co.uk and everything works perfectly!!

Do you have any solution? except "tell users to create .com accounts" or "move a forum to a .pl site"
Jo

We might be banned from the site, could you please provide it's name so I can contact them ?

www.wp.pl for definite. I will have to check, to give you others

Ok, maybe I panicked a little bit. It is "just" the @wp.pl addresses...

bumping it up