Why do I receive "Unknown Date" for emails in Horde?

Question

Why do I receive "Unknown Date" for emails in Horde?

Answer

This occurs when the message is not RFC compliant. Some mail clients work around this by using the received date or some other header timestamp which is why the date may be displayed in mail clients other than Horde.

You would need to contact the support of the application or server that is sending emails that are missing the date header to have them fix the issue on their end.