Just a heads up, we've had an onslaught of automated spambots in our forums of late. If your account is configured to receive notifications of new posts, you'll have noticed the major increase in those incidents of late (we certainly have!). So, in order to address that, we're putting in place some additional anti-spam measures.
The problem with any anti-spam measure is that it may also introduce false positives. If you find yourself getting 503 errors from Virtualmin.com when trying to post, it means you've been caught up in the spam filter (it thinks your IP or email address is associated with a spambot). Hopefully, that will never happen to legitimate users, but if it does, ping us at email@example.com with your details (IP and email address) and we'll try to get it fixed quickly.