With the implementation of the new GDPR data protection law, the whois service has all domain registration data hidden. This means that domain registration data is currently not publicly available.
For this reason, if you are the owner of a domain and need to prove ownership, you can generate a domain ownership document in PDF format from your cdmon control panel.
To generate the document, access your control panel and in the "Basic service list" go to the domain management of the domain for which you want the document.
In the domain management screen, click on the Download ownership document (pdf) option.
When clicking this option, a document like the one shown below will be downloaded, containing the data stored in the Whois database at the time of issuance, where you can see the registrar, document date, domain name, and registrant details.