Managing personal Outlook.com account settings, security, and privacy
Hi,
The "Make Primary " button beside the new address is missing; I can verify this. With the remove button, there should be make primary too.
Could you please click Send feedback on the bottom right to report this? Since the problem is widespread I assume they will fix this pretty quickly.
A friendly reminder that this is a community support forum where users help other users. Advisors participating here cannot make changes to Microsoft services or access internal systems and can only provide technical guidance, independent of Microsoft's Policy decisions.
I hope this information helps. If you have any more questions, don't hesitate to reach out.