What does the error message 'Email not deliverable' mean?

This article provides information on the various causes of the error message 'Email not deliverable' and how to resolve them.

Why is my email not deliverable?

If you receive the error message 'Email not deliverable' this can have several causes. The table below indicates whether the issue lies with the sender, the recipient, or both.

Solutions when the cause lies with the sender

'DKIM required for recipient domain'

• Explanation: You have not configured the required email settings. Some recipients require a DKIM and/or DMARC policy.
• Solution: Follow the support article: 'How should I set up my email?'

Solutions when the cause lies with the recipient

'Security error' or 'Bounced address'

• Explanation: The email address has been blocked by Payt's email partner after a previous failed attempt, possibly because the email address does not exist or the recipient's mail server encountered technical issues. You may find a previous error message in the timeline of the relevant file or past files for the same customer.
• Solution: Verify with the customer if the email address is correct. If so, contact Payt support to check if the address is still blocked and to request unblocking if necessary.

'Network error'

• Explanation: There has been a temporary error on the recipient's side, for example, due to technical issues.
• Solution: Wait and try sending the email again later. If that doesn't work, contact the recipient.

'Mailbox full'

• Explanation: The recipient's mailbox is or was full.
• Solution: Contact the customer so they can resolve this issue.

'User unknown'

• Explanation: The email address likely does not exist or no longer exists. This may happen if the address contains a typo, is outdated, or was incorrectly provided by your customer. If the email address is correct, the issue lies with the recipient. This can also be a temporary problem.
• Solution: Correct the email address in your accounting software if incorrect. If it is correct, contact the customer to check their email settings.

'Host unknown'

• Explanation: The recipient's domain (the part after @) is unreachable, possibly because it is temporarily offline or no longer exists.
• Solution: Check whether the domain still exists and is accessible.

'Expired'

• Explanation: The email was not delivered in time despite multiple automated attempts. Therefore, further attempts will not be made. This usually happens when the recipient's mail server is temporarily unreachable.
• Solution: Contact the customer to check if their email service is functioning normally.

Solutions when the cause may lie with either the sender or the recipient

'Unknown'

• Explanation: There may be various reasons why the error message 'Unknown' is displayed.
• Solution: Contact Payt support to investigate the cause of this issue.

'Blocked'

• Explanation: The recipient's mail server has actively rejected the email, possibly because the sender has been blocked, marked as 'Unwanted' by the recipient, or the email content was flagged as spam. 
• Solution: Contact the recipient to check if they have blocked the sender, or try resending the email if the error message appeared some time ago.