I have a problem with my Microsoft account and all access to Microsoft 365 are locked. I do not know why and when the problem started. Even after I contacted Microsoft support, I do not have the answer for both questions.

What I found, when reporting problem to Microsoft support, there will be a time that it need you to logon to support. How can you do that when your account has been locked?

After I made a call to Microsoft Support, (He also can not help to support. He only tell you how to make a report without account access), there is a way to log report but without signing in.

First of all, go to support.microsoft.com.

Then, at "What do you need help with?", click Microsoft Account icon.

This brings you to another site. Below "Trending Topics", find "When you can't sign in to your Microsoft account" and click it.

In this another site, scroll down until you find "Chat with Microsoft support".

In this site, you need to provide several information including affected email address.

Finally, after submitting the form, chat site appear and you can start to chat with support. However, it depends on how many queue at that moment.

WARNING: This steps only working at this moment only. Microsoft might change the way and site any time.