Forward e-mail from other domain to my domain at Zoho fails with 5.1.0 Address rejected

Forward e-mail from other domain to my domain at Zoho fails with 5.1.0 Address rejected

Hi,

I have my e-mail domain hosted in zoho.com. I have an e-mail account, e.g. aaa@bbb.com. Now I asked somebody else to create an e-mail address for me in another domain, e.g. ccc@ddd.com which automatically forwards to aaa@bbb.com. This setup fails with a "5.1.0 Address rejected". How can I solve this? I can't add the ddd.com domain to my domains as I don't own it and it is not hosted by Zoho.com.

Kind regards,

Fokko