My board (Threads 7) has been up for almost a month now without incident. Today, within the span of a few minutes I've received two e-mails from users who couldn't post. The error message they received is:

Quote
We cannot proceed.
The host from which you are accessing the board is not recognized as a valid host. This is more than likely related to a firewall issue that is blocking the referer variable. Check your firewall settings and try again.

Please use your back button to return to the previous page.


I can post just fine. Is this some security setting on their end, or something else?

Any help will be appreciated, thanks.


Regards,
Rich