Microsoft verification code "we cannot send a text message to this number"

I’ve read through a lot of posts surrounding the topic, but none fully reflect the answer I need. I have a computer lab with Microsoft accounts on each computer. I have one work cell phone that is fully operational.

I get a prompt that the accounts are blocked. (Maybe that should be it’s own forum post.) I go through the process to unblock it. It askes to “Enter your number, and we’ll send you a security code.” I enter the cell phone number and it comes back with "We cannot send a text message to this number." It works sometimes but I get this message a lot. I can instead enter my personal cell phone number and it goes through and the account is unlocked. I don’t think this is a recovery prompt because it seems any number works, but I want my work cell to work. Is there a device limit? Daily limit?

:)