Hi,
What's your account type? POP/IMAP? Do you directly change the server information in Account Settings?
As far as I know, this may be an expected behavior as the new server doesn't know anything about the emails from the old server. Normally, we have to move all emails from your old hosting server to the new one.
Can you log on your account with original server information? If yes, you can add it to Outlook client and then move all original messages to your new account.
Besides, according to my research, it is not recommended to modify the server settings of the existing account. We can create a new account for the new server.
If you have more questions, please feel free to post back.
Regards,
Perry
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