I can not get multi domeins to work

Dear reader,

since days I am trying and trying.
My host is siteground, wp is 3.9.1, main domain inner-link.nl

I purchased an add-on domain, parked via cpanel so that is points to my root web directory.
I configured in the Network admin dashboard under settings multi-domains the new domain: siggis-bikes.com. Then I created a new site an choose the domain siggis-bikes.com. When I enter http://www.siggis-bikes.com I am redirected to inner-link.nl (my main domein). I do not know anymore what to do. Can you help?

Many thanks in advance already!

kind regards,
Markus