The From email address is not valid.

when "From email address:" field is empty so module uses site's email, all works fine. But i can't put other email.
I tried [author-mail] and [mail] and myemail@some.com. Every time i hit "save" on admin/settings/protected_node I get "The From email address is not valid."
Again if leave empty it works well. Please assist
thanks for useful module