Temporarily suspended for unusual activity is Microsoft's account protection triggering, and the path back is designed to be walkable by the real owner, which you are. What triggers it and how to recover:

What triggered it, for understanding rather than blame: sign in from a new country or IP, a VPN, a travel trip, a burst of sends that looked like compromise or Microsoft's systems detecting your credentials in a breach dump elsewhere. None require you to have done anything wrong, the protection errs toward suspending when a pattern looks risky and a legitimate owner recovering is the expected outcome rather than an exception.

The recovery path: the suspension message itself leads to the restore flow, or go to account.live.com and sign in to trigger it. Microsoft asks you to prove ownership through a security code sent to your registered recovery phone or alternate email, entering it clears the suspension. This is why keeping recovery information current matters, the code goes where you told Microsoft to send it and an account with good recovery options is restored in minutes.

The recovery when proofs are missing or outdated: if the recovery phone changed or the alternate email is dead, the account recovery form at account.live.com/acsr is the fallback, a longer questionnaire about your account history, old passwords, contacts you email, subjects of recent mail, that Microsoft reviews to verify ownership manually. Slower and not guaranteed, so answer as completely as possible and it exists precisely for the locked out with stale proofs situation.

The step after recovery: once back in, change the password immediately since the suspension may have followed a real compromise attempt, review the security page for sign in activity you do not recognize, enable two step verification and update the recovery phone and email so the next protective suspension restores smoothly. The suspension being protection working, the lesson is keeping the proofs it relies on current.