Whitelist a Domain in Office 365

  

Aldrich Calvin
Published: June 2nd, 2025 • 6 Min Read

For Outlook 365 users, it is crucial to ensure that important emails are delivered to the primary inbox rather than being filtered into spam. To achieve this, one of the most preferred ways is to whitelist email in Office 365. Whitelisting helps users mark trusted senders, to ensure that their messages won’t move into junk or spam folders. Now, the question is how to whitelist an email in Outlook 365. Do you know the answer? If not, don’t worry, as in this informative journey we will discuss everything that you need to know. Let’s start!

Contrary to popular belief, it is not difficult to whitelist a domain in Office 365. Moreover, domain whitelisting is one of the rare features in M365 that is role-independent. Which means that even users can control which external domains can send email to their account. Before discussing user-level options, let us start off with the steps admins have to take to establish an organization-wide domain whitelist.

Whitelist a Domain in Office 365 via Microsoft 365 Defender Portal

Microsoft 365 Defender is a service used to protect organizations’ data from cyber threats, malware attacks, unauthorized access, etc. Defender for Office 365 will also help in whitelisting the email addresses. Curious to understand how? See the steps below:

• Log in to Microsoft 365 Defender.
  
• Expand Emails and Collaboration > Select Policies and Rules > Open Threat Policies.
  
• Now, open the Anti-Spam policies.
  
• In the flyout window, scroll down and click ‘Edit allowed and blocked senders‘.
  
• Click on Allow Domains.
  
• Click ‘Add domains’.
  
• Type in the name of all domains you want to whitelist in Office 365. Press Add domains.
  
• Press Done.
  
  
• Hit Save.
  
• Close.
  

Use EAC for Organization-wide Whitelisting

Office 365 Admins who are looking to whitelist email in Office 365 for the entire organization simultaneously can opt for this technique. For the same, instructions are as follows:

• Open Exchange Admin Center.
• Under the Mail flow section, select Rules.
  
• Hit the + icon to create a new rule.
• Select Create a new rule to whitelist a domain in Office 365.
• Name the rule (Whitelist Specific Email Addresses).
• Under Apply this rule if…, choose The sender is or The sender’s domain is.
• Enter the email address to the whitelist.
• Under Do the following > Modify the message properties > choose Bypass spam filter, this sets the spam confidence level (SCL) to -1 (which indicates the message is not spam).
• Press Next twice, then click Finish to activate it.
  

How to Whitelist an Email in Outlook 365?

Outlook 365 offers several methods to whitelist an email address, domain, or even organization-wide whitelisting. The following sections describe all the techniques with accurate instructions to whitelist email in Office 365. You can opt for any of them depending on your needs, whether you want to whitelist an email address or a domain. So, let’s dive into them:

Users Can Whitelist a Domain in Office 365 Using Safe Senders List

Adding an email address to the Safe Senders List is the most preferred and straightforward procedure. To do so, follow the steps below:

• Open Outlook > click on the Settings Gear icon > View all Outlook settings.
• Afterward, choose Mail > Junk Email.
• Under Safe Senders and Domains, click on Add.
• Now, you have to type the email address of the sender to whitelist. For example, email address: example@example.com & domain: @example.com.
• Hit Save.

After the completion of this “email to the Safe Senders list” procedure, any email from the selected sender moves directly to the inbox. However, this approach is suited for individuals, not for organizations. To answer the question, i.e., how to whitelist an email in Outlook 365 across the organization, go through the next method.

Whitelist an Email via the Email Settings

For individual users, this is a hands-on approach to answer the query i.e., how to whitelist an email in Outlook 365. In this, you just go to the spam folder and mark the email as Not Junk, and that data automatically moves to your inbox. Detailed steps are given below:

• Open the Junk Email folder in Outlook 365.
• Search the email to whitelist.
• Right-click that email and select Mark as not junk.
• Outlook will prompt to add the sender to the Safe Senders list (if the sender is new).
• Click Yes if you want to whitelist email in Office 365.

Now, we have all the answers to the query,f i.e., how to whitelist an email in Outlook 365. But what if you want to remove the whitelist? Don’t worry, in the next section we will learn the same.

How to Unwhitelist or Remove a Domain from the Safe Senders List?

Sometimes you want to remove an email address or domain from the whitelist. To do so, we discuss the step-by-step instructions given below for removing it from the Safe Senders list:

1. Open Junk Email settings.
2. Search for the email address or domain in the Safe Senders and Domains list > Trash.
3. Save the settings after removal.

That’s all! Now, the selected email address is removed from the Safe Senders list. To whitelist email in Office 365 again, you have to follow the same methods mentioned previously.

Troubleshooting: Common Issues with Domain Whitelisting

As we learned above, how to whitelist an email in Outlook 365? Still, after completing the whitelisting, most of the users faced issues like selected emails still ending up in the spam folder. Likewise, there are more common issues related to the same, we learn all of them and the solutions to solve them:

• Emails from Whitelist Senders Still Go to Junk: This issue happens when another filter is working,g whether Outlook 365 built-in or third-party. So, check the spam filters in Outlook 365, and remove the rule if any.
• Whitelisting Doesn’t Work for Some Domains: This issue persists when a domain is on Microsoft’s blocked lists. To resolve this issue, contact Microsoft support for further assistance.
• Spam Filter Updates: Occasionally, Microsoft updates its spam filtering algorithms, so it is better to check spam filters and settings after the update.

Additional tips to optimize whitelist email in Office 365:

• Use the Categories filter of Outlook 365 to organize emails
• Create Custom Folders for organization
• Enable Focused Inbox for prioritization
• Whitelist only verified senders, and check periodically

Time to Wrap Up!

Now we are at the end of our discussion, and I hope you gained the most valuable knowledge about whitelisting email addresses in Outlook 365. Whitelisting emails in Office 365 is a necessary process for organizations as well as individuals. For anyone who wants to maintain an organized email inbox, whitelisting is a go-to option. In this complete guide, we learned how to whitelist an email in Outlook 365, how to remove a whitelisted email in Office 365, best practices, troubleshooting tips, etc. In short, we covered everything you need to know about the same.