This is Rick a member of the GPWA Membership and Security Team,
The initial review process of your Private Membership application with GPWA has begun.
In order to confirm that the portals submitted are connected with each private membership applicant, we check Whois registration details to verify the registration name matches the applicant’s name. In your case the name doesn’t match or wasn’t available for http://www.casinouniversiteit.com and https://www.jackpotisgevallen.nl/.  We will need another form of confirmation connecting you to this/these site(s). 
The easiest confirmation method is to upload a temporary file named “gpwa.html” to the site and include a brief text message confirming your relationship on that page. We will let you know immediately that we have confirmed the check so you can remove the page.Another method that demonstrates you own or work on the site(s) listed, include a receipt for your hosting or a screenshot taken while logged into your account with the registrar (with the portal domains clearly showing).

Please let me know which approach is most convenient for you.