Zoho Desk incoming emails not arriving

Zoho Desk incoming emails not arriving

While configuring and testing Zoho desk, I have created my departments and their email addresses, but sending an email to any of the addresses for any of the departments doesn't work. I don't receive a response, and no email is fetched nor is a ticket created. I have tried  billing@radaralley.zohosupport.com and support@radaralley.zohosupport.com and I get nothing.