Failed to send message…error – HELP.

I have been using Contact From 7 plug-in to handle a form on my site. All of the sudden it started returning an error message in a red box: “Failed to send your message. Please try later or contact administrator by other way.” What is interesting is I still get the messages that are sent through the form!
Would someone be able to know why the plug in returns error message even though the mail goes trough?

I have tried everything and read all forums out there with no luck to fix the problem.

Here is what I have done:
– called hosting support (godaddy), php and smtp working properly
– uninstalled and deleted the Contact Form 7
– I tried other form plug ins such as CformsII, MM Forms Community and they all produce the same error so the problem is not plugin specific
– I downloaded Configure SMTP. All seems to be working, test e-mail gets to me but it does not fix the problem

Here is my url: http://www.u4ma.com
You can reproduce the problem by filling out the form at the bottom-right of the site.

Any ideas?
Thank you.