DNS resolution problem in launching a domain name

We used Joomla platform to launch a forum site, we were placed on a shared connection. Unfortunately there is this weird problem of some users unable to launch the website, while some are able to launch the site. It will display invalid URL: DNS resolution problem. How can we track the problem , is it from the hosting company or what ?. the site is www.analysethis.co

Sose,

Missed this post, however I've already sent you an email about this. This is purely a DNS problem caused by your hosting provider.

Good luck with the new website and let us know if we can help any further.

Chris.