How to fix Outlook not receiving emails in Office 365

When Outlook in Office 365 suddenly stops pulling in new emails, your whole workflow can get thrown off. It’s frustrating, right?

If Outlook is not receiving emails in Office 365, follow these steps to troubleshoot and fix the issue:

1. Check your internet connection and Outlook’s online status.
2. Update Outlook to the latest version.
3. Review your Junk, Spam, and Deleted folders for missing emails.
4. Free up mailbox storage if your inbox is full.
5. Verify your Outlook account settings and server configuration.
6. Repair or recreate your Outlook profile if needed.
7. Disable problematic add-ins and check security software/firewalls.

You’ll want to figure out the real cause before trying random fixes. Outdated software, corrupted profiles, and messed-up server settings are the usual suspects when Outlook won’t bring in your emails. Let’s walk through the basic steps first, then dig into more advanced fixes if you need them.

Every business has its quirks, so keep in mind that your setup might need something a little different. Our team at NetTech Consultants has helped plenty of organizations get their email flowing again—and we always recommend a few preventive steps to keep things running smoothly.

Essential Steps to Fix Outlook Not Receiving Emails

If Microsoft Outlook isn’t receiving emails, start with these four basic troubleshooting steps. They’ll help you catch most connectivity issues, software compatibility problems, misdirected messages, and even storage limits.

Check Internet Connection and Outlook Online Status

First things first: check your internet connection and make sure Outlook’s actually online. Without a solid connection, your emails just aren’t going to sync.

Test your internet connection by opening your browser and heading to any website. If it’s crawling or just not loading, you’ll need to call your internet provider.

Check your Wi-Fi signal if you’re wireless. Weak signals can make email delivery spotty. Try moving closer to the router—or plug in with a cable if you can.

Look at Outlook’s status at the bottom of the window. If it says “Disconnected,” “Working Offline,” or “Trying to connect,” it’s not talking to the server.

Switch back to online mode by clicking Send/Receive > Work Offline to toggle it off. Give it half a minute or so to reconnect.

Update Outlook to the Latest Version

Running an old version of Outlook? That’s a recipe for email delivery problems, especially with newer security protocols.

Check your version under File > Office Account > About Outlook. Compare it with whatever Microsoft lists as current.

Update via Office 365: Go to File > Office Account > Update Options > Update Now. That should grab and install the latest fixes for you.

Restart Outlook completely once the update finishes. Close every window and reopen it, just to be safe.

Double-check the version again. If the update didn’t stick, grab the latest build from Microsoft’s site.

Turning on automatic updates is the way to go. It’ll save you headaches down the line.

Review Junk and Spam Folders

Outlook’s spam filter sometimes gets a little overzealous and tosses good emails into the junk pile.

Open your Junk Email folder and see if anything important landed there by mistake.

Check your spam filter settings under Home > Junk > Junk E-mail Options. If it’s set too high, you’ll probably miss legit messages.

Mark legit emails as “Not Junk” by right-clicking them in the junk folder and choosing Junk > Not Junk. That helps train Outlook to do better next time.

Add trusted contacts to your Safe Senders list in Junk E-mail Options > Safe Senders. Pop in the emails and domains you actually want to hear from.

Don’t forget to check the Deleted Items folder too. Sometimes filters just delete stuff without warning.

Free Up Mailbox Storage

A full mailbox will quietly block new emails, even if Outlook looks like it’s working fine.

See your mailbox size under File > Mailbox Cleanup. You’ll get a quick snapshot of storage used and what’s left.

Delete old or huge emails from your Inbox, Sent Items, and Deleted Items. Attachments eat up space fast.

Empty your Deleted Items folder by right-clicking and hitting Empty Folder. Stuff in there still counts against your limit until it’s gone for good.

Archive older messages by going to File > Archive. That moves them out of your main mailbox but keeps them handy.

Ask your Office 365 admin about increasing limits if you’re always running out of space. They might bump up your mailbox or set up auto-archiving.

Review and Correct Outlook Account Settings

A lot of Outlook email problems come down to bad account settings. Let’s check your credentials, server configurations, protocol choices, and security settings to get things back on track.

Verify Email Account Credentials

Start by making sure your email credentials are right. Expired or wrong passwords trip up Outlook all the time. Go to File > Account Settings > Account Settings.

Pick your email account from the list and hit Change. Double-check for typos or extra spaces in your address.

Update your password if you’ve changed it recently. Outlook won’t always catch password updates on its own.

Test your settings with Test Account Settings. It’ll try to connect using what you entered and let you know if something’s off.

If you still can’t get in, reach out to your IT admin or email provider for the right login info. Some providers use app-specific passwords, so don’t be surprised if your regular one doesn’t work.

Check Incoming and Outgoing Mail Server Configuration

Server setting mistakes will stop Outlook from connecting to Office 365 or pretty much any provider. Let’s make sure yours are right.

Open account settings and check your incoming mail server address. For Office 365, it’s usually outlook.office365.com (IMAP).

For outgoing mail, use smtp.office365.com.

Here’s what the ports should look like:

Don’t forget to turn on authentication for outgoing mail. Most providers require it for both directions now.

Choose the Correct IMAP or POP3 Settings

Picking the right protocol matters. IMAP works best for Office 365, especially if you check email on more than one device.

IMAP keeps all your emails on the server and syncs changes everywhere. It’s the go-to for anyone who needs access on the go.

POP3 pulls emails to your computer and usually deletes them from the server. Only use it if you stick to one device.

For Office 365, set up IMAP like this:

• Server: outlook.office365.com
• Port: 993
• Encryption: SSL/TLS

If you really need POP3, use outlook.office365.com on port 995 with SSL. But, IMAP is just better for most people using Office 365.

Set Up SSL for Secure Connections

SSL encryption keeps your email safe, and Office 365 (like most providers) requires it now. Let’s make sure your settings are secure.

Turn on SSL/TLS for your incoming mail server. That way, nobody can snoop on your emails while they’re in transit.

Set your outgoing mail server to use STARTTLS. It’s the standard for Office 365 and encrypts your SMTP connections.

Check that you’ve selected My outgoing server (SMTP) requires authentication and Use same settings as my incoming mail server.

After saving, send a test email. If it doesn’t go through, you might have a typo in your SSL settings or a firewall blocking encrypted traffic.

Advanced Troubleshooting Methods

If none of the basics worked, it’s time to dig deeper. Three things to focus on: stubborn add-ins that mess with email flow, corrupted user profiles that break sync, and security software that blocks email traffic.

Disable or Remove Faulty Add-ins

COM add-ins can totally derail Outlook’s ability to fetch emails. We always try launching Outlook in Safe Mode to skip all add-ins and see if emails start arriving.

Hit Windows + R, type outlook /safe, and press Enter. If your inbox suddenly fills up, you’ve found the issue.

To turn off add-ins for good, go to File > Options > Add-ins. Pick COM Add-ins and click Go. Uncheck them one by one, restarting Outlook each time, until you spot the troublemaker.

Once you’ve found the culprit, update it or just remove it. Microsoft suggests only keeping add-ins you actually need for Outlook to run smoothly.

Recreate or Repair Outlook Profiles

A corrupted Outlook profile can block emails from syncing with Exchange servers. We usually try the built-in repair tool first, and if that doesn’t work, we’ll make a fresh profile.

Go to Control Panel > Mail > Show Profiles. Pick your profile, click Properties, then Data Files > Settings > Advanced > Outlook Data File Settings. Hit Compact Now to fix minor issues.

If things are still broken, add a new profile in Control Panel under Show Profiles > Add. Give it a name and set up your Microsoft 365 account.

Before switching profiles, make sure you:

• Export contacts and calendar entries
• Write down any custom rules and signatures
• Note your folder structure
• Back up important emails to PST files

Test the new profile for a day or so before deleting the old one, just to make sure everything’s syncing and nothing important got lost.

Rule Out Antivirus and Firewall Interference

Sometimes, security software just gets in the way and blocks Outlook from connecting to Microsoft servers, so you can’t download your emails. We go through each security component one by one to spot what’s causing the problem.

Try turning off your antivirus email scanning feature for a bit, but leave real-time protection on. A lot of enterprise antivirus solutions come with special Outlook integration, and honestly, it tends to break after updates.

Windows Firewall usually leaves Outlook alone, but third-party firewalls? They’re notorious for blocking it. Add Outlook.exe to the firewall’s exception list—here’s where you’ll usually find it:

• Outlook 2021/365: C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE
• Outlook 2019: C:\Program Files (x86)\Microsoft Office\Office16\OUTLOOK.EXE

The firewall ports Outlook needs:

• Port 993: IMAP over SSL
• Port 587: SMTP submission
• Port 443: HTTPS for Exchange Online

Don’t forget to check if your company’s network firewall blocks these ports. If email works at home but not at the office, you’ll want to talk to your network admin.

After every tweak, send yourself a test email to see if things work. If turning off antivirus fixes it, set up exclusions instead of leaving protection off for good.