Hello @PODA Facilitator,
Welcome to Microsoft Q&A Forum!
Thank you for your message. I’d like to clarify what Microsoft means by “adding a custom domain,” as this can be a bit confusing at first.
When Microsoft refers to adding a custom (work) domain, it means that you would need to purchase a domain from a domain registrar (for example, a domain like yourcompany.com). After that, the domain must be added and verified in the Microsoft 365 Admin Center. Once the domain is added to the tenant, user accounts can be created or updated to use email addresses from that domain, and those accounts can then be used fully with Microsoft Teams and other Microsoft 365 services.
A personal email account or a standalone personal domain email cannot be directly added to a Microsoft 365 business tenant unless the domain itself is first added and verified in the Admin Center. This is why the address you created on your personal domain is not available for scheduling Teams meetings, it is not currently associated with your Microsoft 365 tenant.
Regarding the steps to add a custom domain, the Q&A Assist response has already outlined the process, and you can follow that guidance as a reference.
If you need any help with these steps or have questions about adding a custom domain, please feel free to let me know and I’ll be happy to help further.
Best regards,
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