OX Error Codes - Explained

'Unexpected SMTP server response. Expected: 250, actual: 550, whole response: 550 5.7.1 Reject for policy reason'
 

This error tends to happen when a URL is used in a sent email and is flagged as Spam. This could have been in the email itself, but likely it will have been in the email signature. To test, we recommend removing the signature and sending a test email with only 'test' in the email body, then seeing if it sends fine. If it does, please get in touch with our team and we can ask Open X-Change to unlock this URL so you can send emails again normally.

'Message could not be sent to the following recipients: ["email@domain.co.uk"] (550 - 550 5.7.1) Reject for policy reason'

This error is caused because the mailbox you have tried to email has rejected your email. It's likely a spam issue, so please get in touch with our team and forward over the bounceback you've received to us. We will speak to Open X-Change and ask them to check Vade, their spam provider, for more information