I am testing joomla on my site but whenever a user registers, a message is displayed that the activation link has been sent to mail box but nothing gets delivered, I have check both inbox and spam folder.

The only mail I receive as admin is a notification that a user has registered

Any solution to this?

Don't CMSes come with the option to set up email config? Like. . . choosing to use the smtp protocol or php_mail().
If you're on shared hosting, ask your host to check the server's mail queue manager. If your mails are stuck there then you know wassup. If your mails are not there at all then the mails didn't leave the CMS  camp in the first place so its an in-house problem with your CMS configuration.
I've got a client who has a couple of joomla sites on his reseller account on my server. I'll show him this thread, if he could help.

I am on shared hosting so I will ask my host about what you said.

I just tried the joomla on another webhost and mails are being delivered so I suspect it is from my host

ok, I have set the mail config to smtp and it has started working, thanks

Damn, I'm genius! Why am I mortal?

Whatever mayne, morale: don't blame it all on the host and don't call everything a host's problem or a bug. . . "its not a bug, its a feature"

I will blame it on the host because it worked well on another host with the php mail function

For the reason that it worked on one host and not on the other doesn't mean its a problem, infact it could just mean the other host it worked on has an exploitable vulnerability. Your host (tht it didnt work on) may have seen a security risk in allowing the php mail() on their server (yes, its a security risk!) and may have disabled it or they may have had mails sent from the user of "nobody" blocked still for security risks, they may also be running a firewall which is configured to block some ports. They may also be running "Mod Security" and have set it to block access to a particular kinda header request. These are possibilities and a host who knows what they are doing will not compromise security to please a client. Then again, we complain about Nigerian host companies for their lack of technical know-how. How about the Nigerian clients for their lack of understanding of how these things work?

Was that question meant for me? Rhetorical. I understand your explanations.

Now I can sleep well after weeks of annoyance . I thought the host was possessed by demons .