A fully managed end-to-end service for digitally signing code, documents, and applications. (formerly Trusted Signing)
Hey there, Kochi Pochi
Please can you sign into your work account here: https://mysignins.microsoft.com/security-info
Once you have signed in, it should load your security info page where you can see your sign-in methods. Please can you click onto 'Add sign-in method' on your account
Once you have added MFA, to the account. Please can you try signing into your account on the admin portals again. It should allow you to authenticate and sign into the admin portals.
Hope this helps,
Nathan