For an Outlook.com account that was recently flagged for suspicious activity and is no longer receiving mail, the most likely causes in the provided guidance are:
- The account is still blocked or partially restricted due to unusual sign-in activity.
- The mailbox or Microsoft cloud storage is full, which stops new mail from being delivered.
Take these steps in order:
- Check if the account is blocked and unblock it
- Sign in to Outlook.com in a browser.
- If prompted that the account is blocked or needs verification, follow the prompts or use the official unblock flow described in Unblock my Outlook.com account.
- Use the Sign-in Helper: Sign-in Helper from the unblock article to complete verification and remove any remaining block.
- Confirm storage is not full
- If Microsoft cloud storage (Outlook.com mailbox + OneDrive) is full, no email can be sent or received and messages sent to the account are bounced and unrecoverable.
- Check mailbox storage using the storage link in Can't send or receive email in Outlook.com and free up space (delete large messages, empty Deleted Items and Junk Email, and remove unnecessary OneDrive content) until under the limit.
- Wait out any temporary lockout and avoid repeated attempts
- If there were many recent sign-in, password reset, or recovery attempts, the account may be in a temporary protection lockout.
- The recommended action from similar cases is to wait at least 24 hours with no further sign-in or recovery attempts, then sign in again and re-test mail flow.
- Re-test mail delivery from multiple senders/devices
- After unblocking and confirming storage is not full, send test messages:
- From another external email service to the Outlook.com address.
- From the Outlook.com account to itself.
- Check Inbox, Junk Email, and other folders.
- After unblocking and confirming storage is not full, send test messages:
- If still not receiving mail after unblocking and freeing space
- Use the Microsoft account sign-in helper mentioned in Can't send or receive email in Outlook.com to confirm there are no remaining sign-in issues.
- If the account remains blocked or mail still does not arrive after 24+ hours and after following the unblock steps, use the support options referenced in Unblock my Outlook.com account (for example, via the links there such as When you can't sign in to your Microsoft account) to continue recovery.
Direct phone escalation for consumer Outlook.com accounts is not described in the provided material; recovery and unblocking are handled through the automated online flows and the Sign-in Helper.
References: