It's often the case that in order to diagnose issues with an email message, you need to access the message headers or source. If you're in LuxSci webmail, you can access these very easily. Select a message down here in the message view pane. Click in the headers tab, this gives you all of the headers of the message, which show all of the raw delivery information and other metadata like subject, from, to, date et cetera. You can select these all and copy and paste them into an email message to a support person.
If you go under the settings gear tab, you can also click on download message. This will allow you to save a message as an EML file. This is the raw contents of the entire message, the headers and the body, and all attachments. This provides even more information that can be used for diagnosing things. It can also be used for importing messages into other email programs.