I have been trying to import my archived emails (MS Exchange) to gmail using Outlook. I have created an IMAP account for gmail within Outlook and copied the old mails into there. But I came to the following problem which is quite annoying:

The emails sent by myself, which appear absolutely fine in the archived folder, are shown as "on behalf of first name surname" under the subject field. I have check the message header. It seems both the "From" and "Sender" fields become text only in the format of "first name surname" without the real email address of mine.

I have also tried to copy these emails to an Outlook folder, but no such problem. So it appears to have something to do with alien accounts only.

I wonder if there is a way to retain the real addresses when moving/copying emails across (and get rid of the annoying "on behalf of")? Anyone kindly help me with it? Thanks in advance!