Blacklist email address office 365

To blacklist an email address in Office 365, you can use the following methods:

Method 1: Using the Office 365 Security & Compliance Center

  1. Sign in to the Office 365 Security & Compliance Center with your admin credentials.
  2. Go to the "Protection" tab and click on "Spam filtering".
  3. Click on "Junk email" and then click on "Edit" next to "Blocked senders".
  4. Enter the email address you want to blacklist in the "Add a sender" field.
  5. Click "Add" to add the email address to the blocked senders list.

Method 2: Using PowerShell

  1. Open PowerShell and connect to your Office 365 tenant using the following command: Connect-ExchangeOnline -UserPrincipalName <your_admin_username> -ShowProgress $true
  2. Run the following command to add the email address to the blocked senders list: Set-ThrottlingPolicy -Identity "Default" -BlockedSenders @{Add="[email protected]"}
  3. Replace "[email protected]" with the email address you want to blacklist.

Method 3: Using the Office 365 Admin Center

  1. Sign in to the Office 365 Admin Center with your admin credentials.
  2. Go to the "Admin centers" tab and click on "Exchange".
  3. Click on "Mail flow" and then click on "Rules".
  4. Click on "New rule" and select "Block or allow" as the rule type.
  5. Enter the email address you want to blacklist in the "From" field.
  6. Click "Save" to save the rule.

Note: When you blacklist an email address, it will be blocked from sending emails to your organization. However, if the email address is already in your organization's address book, it will not be blocked.

Also, keep in mind that blacklisting an email address is a global setting that applies to all users in your organization. If you want to block an email address for a specific user or group, you can use the "Junk email" settings in the user's mailbox settings.