I have two addresses ....@talktalk.net. I mostly use Outlook on my desktop. When sending from either of these I get the "550 5.7.1 Reject for policy reason" for various recipient addresses: generic e.g. sky.com, or specific organisation/domain names. Messages to Gmail addresses seem to go through OK.
This does not happen if send using webmail; so far the addresses I have used for test messages have gone and been received OK.
Looking through the forum this seems to be a common problem.
