Same problem here
Unable to identity verification by phone
I would like to add a subscription account for my business, however everytime I pressed the "Start free" button, I am directed to a sign up page and are always unable to verify my phone.
No matter I selected "Text me" or "Call me", it all shows "We're unable to validate your phone number" with no luck.
I don't have a local call or a office phone, the only number I have is my fking phone number that you don't accept.
I had cleaned up my browser cookies, caches, and tried using another browsers, using cell phone, made several phone calls to microsoft support and still stuck at signing up.
It's been months, please find and solve the problem.