DKIM - DomainKeys Identified Mail verification fails with portfoliobox

DKIM - DomainKeys Identified Mail verification fails with portfoliobox

Hi, I sent the TXT Record and Selector name to my DNS (portfoilibox), the DKIM Core Key Record is checked and it is valid. But verification fails. The Portfoliobox team replied: the record has a proper value and applied to a correct sub-domain. Can you please check with Zoho if they can give us any clue why verification doesn't work?

I contacted Zoho via CONTACT US twice but haven't heard back yet.

Can anyone help me with that? Thank you!
Marina