I followed the steps on your help page and when I try to verify my DKIM, Zoho tells me the verification failed. When I check with  http://dkimcore.org/tools/keycheck.html and I put in my selector "zoho" and my domain "onetwentyeight.de" it tells me: "this is a valid DKIM Record". So why does Zoho take issue with my DKIM Record?

Greetings

Martin