Not receiving email due to outbound spam

To restore normal mail flow and protect the account after a hack, focus on three areas: securing the Microsoft account, cleaning up malicious changes in Outlook/Outlook.com, and unblocking the mailbox if it was flagged for spam.

1. Secure the Microsoft account

• If there is any suspicion that the attacker still has access, change the password again using a trusted device and network.
• Keep two‑factor authentication (2FA) enabled.
• Follow the official guidance for compromised accounts to ensure all security info (phone, alternate email, authenticator) is correct and that no unknown methods are added. If access is lost again, use the official recovery process described in the hacked/compromised account guidance.

2. Clean up malicious mailbox configuration Attackers often set rules or forwarding that continue to send spam or exfiltrate mail even after a password change.

• Sign in to Outlook on the web.
• Check Settings → Mail → Rules and delete any suspicious rules (for example, rules that auto‑forward, auto‑delete, or create drafts, like the “Demon” rule described in a similar case).
• Check Mail → Forwarding and remove any unknown forwarding addresses.
• If available, use Sign out everywhere in the Microsoft account security settings to terminate all active sessions.
• Review app permissions and revoke any apps that are not recognized.

If using Microsoft 365 with admin access:

• In the Exchange admin center, review Mail flow → Rules for suspicious rules.
• Use PowerShell (as in the referenced guidance) such as Get-InboxRule -Mailbox youraddress@example.com to find and remove hidden or malicious rules.

3. Address the outbound spam block / not receiving email If the account was sending spam, the service may have temporarily blocked sending or even affected receiving:

• For Outlook.com accounts, if the account is blocked due to suspicious activity, use the Sign-in Helper to unblock it as described in the Outlook.com unblock article.
• Ensure mailbox and cloud storage are not full; if storage is full, sending and receiving will stop until space is freed.
• After unblocking and cleanup, monitor the account for any new unusual drafts, rules, or sign‑in prompts.

If access is lost again or recovery fails, follow the official “recover a hacked or compromised Microsoft account” guidance and, if necessary, contact support as described in the referenced Q&A answers.

References:

• Unblock my Outlook.com account
• Can't send or receive email in Outlook.com
• Hacker set up continuous draft ransomware email - Microsoft Q&A
• My personal hotmail account hacked by hacker with authentication app enabled. - Microsoft Q&A
• My account got hacked - Microsoft Q&A