Not receiving emails with attachments?

Not receiving emails with attachments?

I have not made any changes to my account or anything. Just a few hours ago someone who was trying to send me an attachment (just a word document) and they got the following message:
Delivery to the following recipient failed permanently:

     [my zoho email was written here]

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the server for the recipient domain powerbackproductions.com by mx.zohomail.com . [IP was written here].

The error that the other server returned was:
554 5.2.3 MailPolicy violation Error delivering to mailboxes

I tested it by sending myself a text only email and it worked, but it attachments wont go through, please help asap my email cannot be down this long, I also tried deleting some emails in case my inbox was too full but it still did not work.