cacaedu
Hello
First issue that the thsite.top certificate you requested is not for the domain that is on your account (The spelling is different). However, if the is-best domain is the one you want the certificate for, then that one is setup correctly.
Next, In order to issue a certificate, you need to verify that you own the domain with the certificate authority (In this case, it is GoGetSSL). If you go to the page you screenshotted and select the “Processing” button, you will be prompted to set CNAME records on your domain to verify you own it. After the verification passes, the provider (GoGetSSL) will issue the certificate, which you can then install.
Please let me know if you need any additional assistance!