This site has been up and running fine since January. Until recently my client noticed the registration emails stopped working. I've tested and found that Joomla emails are working fine. And when you click 're-send confirmation email', that works. Only when a user registers that they don't get the registration email. I turned on debugging and turned error reporting to max. Checked the error log. No errors anywhere. It makes no sense why it would just stop working. Only thing done during that time was updating CB and updating Joomla.

I've tried updating PHP to the latest version. Tried switching to the default template. I can't see anything other than updates causing the bug/issue.

Info: CB & Joomla are latest version.

Thanks for such a quick response, Kyle. That was my first thought, but when I found that system emails and re-send confirmation emails were working, I dismissed the server as being the issue. I had tried to find mail server logs in my cPanel, but I'll give them a call since it's probably something I can't get to. I can see your theory being correct, though, as they do seem to have overzealous security when it comes to sending emails. I'll post the outcome.

Just an update... My host looked at the email logs on the server. I was correct in thinking that I don't have access to that on a shared account, by the way. So, when I send a test mail from the system, he sees it go through. But when I register (and don't get the registration confirmation email), he doesn't see anything at all. In case there is something happening in the hosting account, he did create a ticket. But I have a feeling without any log of the email, they won't be of much help. Will have to see what they say. I'm using PHP mail, by the way, in case I didn't mention that earlier.

Good idea. I'll try that next time I can re-visit the issue and pose the outcome.