Unblock a Sender in Outlook 365: Step-by-Step

To unblock a sender in Outlook 365, remove their email address or domain from your blocked senders list. In Outlook on the web or new Outlook for Windows, open Settings > Mail > Junk email, find the sender under Blocked senders and domains, and remove the entry. In classic Outlook for Windows, use Home > Junk > Junk E-mail Options > Blocked Senders. This lets messages from that sender reach your inbox if no other junk-mail rule or organization policy blocks them.

Unblocking changes the junk-mail setting for your mailbox; it does not retrieve messages already deleted or guarantee future messages will land in the Inbox. You can check the Junk Email folder and mark a legitimate message as not junk as a separate step. The instructions below cover the Microsoft 365 versions most people use, and explain the differences between the updated and classic Outlook apps.

What You’ll Need

Access to the Outlook mailbox where the sender was blocked. If you have several Microsoft accounts, check that you are signed in to the right one.
The sender’s exact email address, or the domain you want to unblock. If you do not know it, look in an old message or in the blocked list before removing anything.
A web browser or Outlook app. You may need to contact your Microsoft 365 administrator if a work or school organization manages its own mail-blocking policies.

Step-by-Step

Confirm which mailbox and Outlook version you are using. Open Outlook and check the account shown in the app, especially if you have more than one mailbox connected. Outlook on the web is the browser version at Outlook on the web; new Outlook for Windows has a similar Settings panel. Classic Outlook for Windows has the traditional ribbon and a Junk menu on the Home tab. The steps differ, so follow the matching route below.
Open the blocked-senders list in Outlook on the web or new Outlook. Select the Settings gear near the upper-right corner. In the Settings panel, choose Mail, then Junk email. Find the section called Blocked senders and domains. If you do not see Mail immediately, use the Settings panel’s search field to look for Junk email. This list contains addresses and domains that Outlook treats as blocked for this mailbox.
Remove the exact blocked entry. Look through Blocked senders and domains for the sender’s full email address. Select the entry and use the Remove, Delete, or trash-can control shown beside it, depending on the version of Outlook. If the list has separate entries for senders and domains, check both. Removing a domain entry can allow mail from every address at that domain, so remove only the entry you intend to unblock. If the sender is not listed, do not add them to the blocked list by mistake; move on to the checks in Troubleshooting.
Save or confirm the change if Outlook asks. In many current Outlook web and new Outlook screens, removal takes effect as soon as you delete the entry. If a Save button appears, select it before leaving Settings. Close the Settings panel when the change is complete. Reopen Junk email if you want to verify that the address or domain no longer appears in the blocked list.
Use classic Outlook for Windows if that is your app. In the main Outlook window, select Home on the ribbon, then Junk > Junk E-mail Options. Open the Blocked Senders tab. Select the sender’s address or domain and choose Remove. Select Apply, then OK, if those buttons are available. The Blocked Senders list in classic Outlook is the place to remove a blocked entry; deleting a message from the Junk Email folder alone does not remove it from this list.
Check the Junk Email folder for messages already filtered. Go to the folder list and open Junk Email. If you find a message from the sender, open it or select it and choose Not junk, Not junk email, or the equivalent option shown in your Outlook version. If prompted, confirm that the sender is trusted. This can help correct the treatment of that particular message, but it is not a substitute for removing the address from Blocked senders and domains when it is listed there.
Send or request a new test message. Ask the sender to send a fresh message after you remove the block. Check the Inbox and Junk Email folders, and allow a little time for delivery. If the message still does not arrive, search all mail folders for the sender and use the troubleshooting checks below. A message that was blocked or deleted earlier may not reappear just because you unblocked its sender.

On Outlook for Mac: The exact controls vary between versions. In classic Outlook for Mac, check Outlook > Settings or Preferences > Junk Email, then look for the blocked-senders list and remove the address. If your version does not show that route, open the same mailbox in Outlook on the web and follow the web steps above. Changes made to an Exchange or Microsoft 365 mailbox’s junk settings may sync across Outlook clients, but local settings and older app versions can behave differently.

Common Mistakes

Removing the wrong kind of entry. A blocked list may contain a full address, such as person@example.com, or a whole domain, such as example.com. If only the address is blocked, removing a similar-looking domain entry may be unnecessary. Conversely, removing one address will not unblock other addresses from the same domain if the domain itself is listed separately.
Assuming that moving one message unblocks the sender. Dragging a message out of Junk Email or selecting Not junk can affect that message’s classification, but the sender can remain in the blocked list. Check and remove the list entry as well.
Looking in the wrong account or profile. A sender blocked in a personal Outlook.com mailbox may still be blocked in a separate work mailbox, or vice versa. Make the change while signed in to the account that receives the unwanted or missing messages.
Expecting previously missing mail to be restored automatically. Unblocking affects future filtering. It does not necessarily restore messages that were deleted, quarantined, or rejected before you changed the setting.
Unblocking an entire domain unintentionally. A domain entry applies more broadly than a single sender address. Check what the entry represents before removing it, particularly in a work mailbox where the domain may include many senders.

Tips

Copy the sender address from a genuine earlier message, or inspect the blocked entry carefully, rather than relying on a display name. Display names can be shared or spoofed; the email address is the useful detail for matching the list.
If you want messages to be easier to find rather than automatically trusted, create an inbox rule or use a folder instead of broadly allowing a domain. A rule can organize mail, but it cannot override every organization-level security policy.
For a sender whose messages repeatedly go to Junk Email, use Not junk on a legitimate message and review both the blocked list and any rules that move or delete mail. Do not mark suspicious messages as safe simply because they appear to come from a familiar name.
After a change, test with a new message and check Junk Email, Deleted Items, Archive, and any custom folders. This helps distinguish a junk setting from an inbox rule or a message that was moved manually.

Troubleshooting

The sender is not in the blocked list. Check whether the message is being sent to a different alias or mailbox, and search Outlook for the full address. Review Junk Email for the message, then check Settings > Mail > Rules in Outlook on the web or new Outlook for rules that move or delete messages. In classic Outlook, inspect Rules & Alerts from the Home ribbon. Also check whether a Focused Inbox, a custom folder, or a connected mail app has moved the message. The blocked list is only one possible reason mail is missing.

You removed the entry, but new mail is still missing. Confirm that the right account was changed and that the entry is gone. Ask the sender to verify the address they used and to send a new message, not just rely on an earlier message. Search all folders, including Junk Email and Deleted Items. For a work or school account, your organization’s Microsoft 365 administrator may have a mail-flow rule, quarantine policy, or security block that overrides personal junk settings. Ask the administrator to check message trace or quarantine if available; only an administrator can change some organization-wide restrictions.

The blocked-list controls are missing or the change will not save. Refresh Outlook, reopen Settings, or try Outlook on the web in a current browser. In classic Outlook, confirm that you opened Junk E-mail Options for the correct account or profile. If you can view the list but cannot edit it, your organization may restrict the setting, or the app may be having a sign-in or sync issue. Sign out and back in only if you know your account credentials and can complete any required multifactor authentication. If the problem continues, contact your administrator or Microsoft support rather than repeatedly changing unrelated junk settings.

A message is in quarantine rather than Junk Email. Quarantine is different from the mailbox Junk Email folder and may be controlled by your organization’s security tools. Follow your organization’s quarantine notification or ask the administrator to review the message. Removing a personal blocked-sender entry will not release a message held by an administrator-managed policy.

Frequently Asked Questions

Does unblocking a sender restore old messages?
No. Removing a blocked entry changes how future messages are treated. Look in Junk Email, Deleted Items, and any quarantine or retention tools for an earlier message. If it is no longer available, ask the sender to send it again.

Will the sender know that I unblocked them?
Outlook does not normally send the sender a notification when you remove their address from your blocked list. They may only notice that a new message is delivered if they send one and it is not stopped by another filter or policy.

Is unblocking the same as adding someone to Safe Senders?
No. Unblocking removes an entry that explicitly blocks an address or domain. Adding an address to a safe-senders list is a separate setting and may help with ordinary junk filtering, but it does not necessarily override organization security controls or every mailbox rule.

Can I unblock a sender in the Outlook mobile app?
Mobile app controls can differ by version and account type. If you cannot find the blocked-senders list in the app’s settings, use Outlook on the web in a browser, sign in to the correct mailbox, and remove the entry under Settings > Mail > Junk email.

Why does mail from the sender still go to Junk Email after I unblock them?
Another junk-filter decision, a mailbox rule, a sender authentication issue, or an organization policy may be responsible. Check that the block is removed, mark a legitimate message as Not junk, review your rules, and ask your administrator to investigate if it is a work or school mailbox.

Should I unblock a whole email domain?
Only if you want to allow messages from all addresses at that domain and trust them. If you only need mail from one person, remove that person’s exact address instead. Domain-level changes are broader and may allow unwanted messages from other senders using the same domain.

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