Won't send mail

Before you say there’s a problem on the server :), it works on one of my sites, but not on another on the same server, so it’s not a systemwide server issue.

I have one site where I don’t need the plugin, but it works just fine.

On my other site, no other contact form works OTHER than cforms ii and cforms is using the same wp_mail function that this plugin uses. I want to migrate from cforms ii for various reasons, but I cannot as it’s the only one that will send mail.

The mail is just not being sent as there is no mail error log nor is mail being bounced back or sent to spam folder.

I want to use this plugin as well as uservoice (but neither work). Not sure what the issue is. I’ve hired a server admin to look at it and neither of us can figure out what the difference is between the two accounts that would allow one to send mail and the other not to.

Any ideas would be most helpful!

Thanks!

http://wordpress.org/extend/plugins/visual-form-builder/