Finally updated all of my WP sites to v3.0.4 over the weekend, and now none of my contact forms work. Well ... in fact, they still work according to the sites, but no e-mails appear in the appropriate inboxes once they have been submitted.
Obviously, I don't know whether the problem has only arisen with the update, as there is no indication of a problem until the forms are tested, and I did not test them immediately prior to the updates.
I have been using (successfully) cforms for the last year or so and this has worked brilliantly. In an attempt to solve the problem, I installed Custom Contact Forms on one of the sites, and the same problem exists.
Custom Contact Forms logs submission of the forms in its own system, but still no e-mails are sent out.
I have tried both WordPress Default mailing option, and SMTP, with zero success ... and I have raised a ticket with my webhost to see if this is a problem at their end.
Anyone got any ideas ... getting desperate here.