I have built a new website for my client, who has an email address like his_address@zohomail.eu (example).

When his customers use the Contact Form on his website, the notification emails are sent to an address as his domain name, and the Webhost automatically forwards them to his Zoho email address.

However he never receives any of these automatically forwarded emails. 

I have checked with the Webhost (who has outstanding and highly rated Customer Support) and they have confirmed that everything is setup perfectly, and the emails should be arriving in his Inbox.

The Webhost thinks that Zoho Email may possibly be blocking any email that is "forwarded".

While troubleshooting I also tested skipping the forwarding step, and having the website send the emails directly to Zoho email, unfortunately that didn't work either.

Of course, we also checked the spam folder.

Any help or guidance that leads to solving would be greatly appreciated.

Thank you.