Using New Outlook on Windows for professional communication and productivity
Dear Tom Girvan,
In New Outlook for Windows, moving email messages between separate accounts is blocked by default whenever a work or school account is involved. This behavior is part of the application’s security design and is intended to help protect organizational data from being transferred between accounts without the appropriate authorization.
Although you may have administrator privileges, these permissions do not automatically enable the feature. Administrator access and the security setting that controls cross-account message transfers are managed separately. As a result, the restriction may remain in place even when you are signed in as an administrator.
Kindly refer to this article to turn on the feature: Supported accounts in new Outlook for Windows | Microsoft Learn
I hope the information shared helps point you in the right direction.
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