ERROR: A message that you sent could not be delivered (please help!)

ERROR: A message that you sent could not be delivered (please help!)

When I send an invoice from Paypal to my clients, I receive this message:

This message was created automatically by mail delivery software. 
A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. 

service@paypal.com.au INVALID_ADDRESS, ERROR_CODE :550, ERROR_CODE :#5.1.0 Address rejected. 



Received:from mail.zoho.com by mx.zohomail.com 
    with SMTP id 1480715387078937.788346479248; Fri, 2 Dec 2016 13:49:47 -0800 (PST) 
Message-ID:<158c183c08c.e777ce8c1266.5840660559750526731@happyandauthentic.com
Date:Sat, 03 Dec 2016 05:49:47 +0800 
From:Happy and Authentic™ <connect@happyandauthentic.com
User-Agent:Zoho Mail 
To:<service@paypal.com.au
Subject:Thank you for contacting Happy and Authentic™ Re:You’ve sent an invoice (1601) to Louis Nelson Smith for $3,000.00 AUD 
Content-Type:multipart/alternative; 
    boundary="----=_Part_33848_2096089267.1480715387028"

Does that mean they didn't receive my invoice? Please help me fix this quick! My business is in jeopardy!