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Unfortunately, if your old email account was your primary alias and it is no longer valid, you may encounter difficulties changing to your new email as the primary alias. Microsoft does not allow the merging of accounts or the recycling of aliases. If you have already added your new email address to your account but cannot set it as the primary alias, it may be due to restrictions in Microsoft's policies regarding alias management.
You might want to ensure that your new email is properly verified and that there are no outstanding issues with your Microsoft account that could be preventing this change. If the problem persists, contacting Microsoft Support directly may provide you with the necessary assistance to resolve your issue.
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