The problem is you don't have the subdomain in the URL you are giving
You need to start the URL with www
(which is the subdomain)
An example
By URL, http://superuser.com is different to http://www.superuser.com, and could actually point to different servers and serve totally different content (usually it makes sense to point to the same location).
Most people assume a website starts with www.
and some assume it doesn't need www.
- Neither are actually true. Convention suggests we should always have www.
and ideally always accept when no subdomain is present (although I appreciate there are reasons not for things like SSL issues and SEO issues etc).
I also emailed that company to inform them (in case they decide to react to it)
In your post you wrote mytraveline.mobi
which is what I assume is the URL you're trying to reach. Currently mytraveline.mobi shows an IIS page, where as www.mytraveline.mobi shows the website as you expect.