For a few months now we have been having problems with users being able to receive emails from this site - most problematic being confirmation and password reminder emails.
We have had discussions with our host who, although admit they have a problem, do not see it as their concern to resolve.
We are now looking at an alternative solution which we wish to implement as soon as we can. Meantime, if you have any such issues, please contact us via the contact form (this appears to work!) and we will attempt to help you out.