title: Email rejections after moving MX record
body: <p>I recently moved my email from my own domain (hosted with Vidahost) to Exchange Online. Everything seems to be working fine with regards to genuine email arriving at my Exchange account, however I am getting strange mail rejection notifications on my Vidahost account.</p>
  
  <p>The MX record has been changed correctly and there is only 1 record, so I'm a bit confused how the rejections are coming back to Vidahost? An example is as follows (from CPanel Email Trace):</p>
  
  <pre><code>Email was rejected at SMPT time by an RBL, filter or other configuration
  Event: rejected
  User: -remote-   
  Sender: (random invalid addresses, progresses through alphabet)eg huggins @ mydomain  
  Sender Host: customer-189-217-55-58.cablevision.net.mx   
  Sender IP Address: 189.217.55.58  
  Authentication: unauthorized 
  Spam Score: 0 
  Recipient: as sender  
  Router: reject  
  Transport: **rejected**  
  Delivery Host: customer-189-217-55-58.cablevision.net.mx  
  Delivery IP Address: 189.217.55.58 
  Size: 0 bytes 
  Result: JunkMail rejected - (customer-189-217-55-58.cablevision.net.mx)   [189.217.55.58]:38159 is in an RBL, see http://dnsbl.invaluement.com/lookup/?item=189.217.55.58 
  </code></pre>
  
  <p>A vast majority of the recipient and senders are set to invalid accounts on my domain, but none are actually originating from my domain (the host has also verified this). Exchange Online is rejecting any email sent to a non-account on my domain, how are these then making their way back to Vidahost even though the MX record doesn't point there?</p>
  
  <p>Any help greatly received!</p>