Please find the below steps to collect the internet message header associated with an email
In Outlook for Office 365, 2016, 2013, or 2010 on a PC
1. Double-click an email message to open it outside of the Reading Pane.
2. Click File > Properties.
3. Header information appears in the Internet headers box.
Tip: You can highlight the information in that box, press Ctrl+C to copy, and paste it into Notepad or Word to see the entire header at once.
4. Include a copy of this header into this ticket response and we will take it from there.