30 Jun Outlook Not Sending or Receiving Emails? Common Causes and Fixes for Businesses
If Outlook is not sending or receiving emails, it can quickly disrupt your business. Whether emails are stuck in the outbox, new messages are not arriving, or Outlook keeps asking for a password, the issue can usually be traced back to Microsoft 365, mailbox settings, internet connectivity, DNS records, or device configuration.
At Digital Office Group, we support businesses with Microsoft 365, Outlook, Exchange Online, email security, device management and ongoing IT support. This guide explains the most common reasons Outlook stops working and what your business can do to fix the issue.
Why Is Outlook Not Sending or Receiving Emails?
Outlook email issues can be caused by a number of different problems. Some are simple user-level issues, while others may require technical investigation from your IT support provider.
Common causes include:
- Poor or unstable internet connection
- Microsoft 365 service issues
- Outlook working offline
- Incorrect mailbox password
- Mailbox storage being full
- DNS or domain problems
- Outlook profile corruption
- Large attachments stuck in the outbox
- Security or multi-factor authentication issues
- Problems with Exchange Online licensing
1. Check Your Internet Connection
The first step is to check whether your internet connection is working correctly. Outlook relies on a stable connection to send and receive emails through Microsoft 365 or Exchange.
If web pages are loading slowly, Teams calls are dropping, or other cloud services are affected, the problem may not be Outlook itself. It could be a wider broadband, Wi-Fi, firewall or network issue.
For businesses, repeated internet problems can cause wider disruption across email, VoIP phone systems, cloud applications and remote working. If this happens regularly, it may be worth reviewing your business broadband, leased line or network setup.
2. Make Sure Outlook Is Not Working Offline
Outlook has a “Work Offline” mode. If this has been turned on accidentally, Outlook will stop sending and receiving new emails.
To check this:
- Open Outlook.
- Go to the Send / Receive tab.
- Look for the Work Offline button.
- If it is highlighted, click it to reconnect.
Once Outlook is back online, try sending and receiving again.
3. Check If Emails Are Stuck in the Outbox
If Outlook is not sending emails, check the Outbox. A message may be stuck due to a large attachment, poor connection, or mailbox issue.
If a large email is stuck:
- Open the Outbox.
- Delete or move the stuck message to Drafts.
- Try sending a smaller test email.
- Use OneDrive or SharePoint links instead of large attachments.
For businesses using Microsoft 365, sharing files through OneDrive or SharePoint is usually more reliable and secure than sending large attachments by email.
4. Check Microsoft 365 Service Health
If multiple users in your business suddenly stop receiving emails, the issue may be with Microsoft 365 rather than individual devices.
Common signs of a wider Microsoft 365 issue include:
- Several users affected at the same time
- Outlook and Teams both having issues
- Webmail also not working
- Emails delayed across the business
- Users unable to log in to Microsoft 365
Your IT provider can check the Microsoft 365 admin centre, review service health, confirm whether Exchange Online is affected, and advise whether the issue is local or Microsoft-related.
5. Check Your Mailbox Storage
If your mailbox is full, Outlook may stop sending or receiving emails. This is especially common for users who have many years of emails, large attachments, or shared mailboxes.
Signs your mailbox may be full include:
- New emails not arriving
- Outgoing emails bouncing
- Outlook warning that mailbox storage is full
- Shared mailboxes not updating correctly
Possible fixes include archiving old emails, deleting large attachments, reviewing retention policies, or upgrading the Microsoft 365 licence if more mailbox storage is required.
6. Restart Outlook and Your Device
It sounds simple, but restarting Outlook and the device can often clear temporary sync issues. Outlook may fail to connect properly after updates, sleep mode, VPN changes or network interruptions.
Before deeper troubleshooting, close Outlook fully, restart the computer, then reopen Outlook and send a test email.
7. Try Outlook on the Web
If the Outlook desktop app is not working, try logging into Outlook through a browser. This helps identify whether the issue is with the mailbox itself or the local Outlook application.
If Outlook on the web works, but the desktop app does not, the problem may be with:
- The Outlook profile
- Local cache files
- Office installation
- Windows updates
- Add-ins causing Outlook to freeze or crash
If neither Outlook on the web nor the desktop app works, the problem may relate to Microsoft 365 licensing, authentication, mailbox permissions, DNS or a wider service issue.
8. Check Password and Multi-Factor Authentication
If Outlook keeps asking for a password, the issue may be linked to Microsoft 365 authentication. This can happen after a password change, account lockout, expired credentials, or multi-factor authentication change.
Businesses using Microsoft 365 should also ensure that users are protected with secure sign-in policies, conditional access and multi-factor authentication. However, these settings need to be configured correctly to avoid locking users out unnecessarily.
Digital Office Group can help with Microsoft 365 setup, secure authentication, MFA, conditional access, account recovery and user support.
9. Review Outlook Add-ins
Some Outlook add-ins can cause sending, receiving or performance problems. This is common with older CRM plugins, PDF tools, email signature software or third-party security tools.
If Outlook opens slowly, freezes, crashes or fails to send emails, add-ins may be part of the issue. Your IT support provider can test Outlook in safe mode and disable problematic add-ins.
10. Check Email Rules and Junk Settings
If emails appear to be missing, they may not actually be lost. Outlook rules, junk settings or focused inbox settings may be moving them automatically.
Check:
- Junk Email folder
- Deleted Items
- Archive folder
- Focused and Other inbox tabs
- Mailbox rules
- Shared mailbox rules
In some cases, malicious mailbox rules can be created after an account compromise. If emails are being forwarded externally or deleted automatically, your account should be reviewed immediately.
11. Check DNS Records for Your Domain
If your whole business is not receiving emails, the issue may be related to DNS records. These records tell the internet where to deliver your email.
Important email DNS records include:
- MX records
- SPF records
- DKIM records
- DMARC records
- Autodiscover records
Incorrect DNS settings can cause emails to bounce, fail authentication, land in junk, or stop arriving altogether. This is particularly important after moving to Microsoft 365, changing domain providers, migrating websites, or switching IT suppliers.
12. Check Microsoft 365 Licensing
If a user’s Microsoft 365 licence has been removed, expired or incorrectly assigned, Outlook may stop working. Businesses should regularly review licence allocation to make sure users have the right level of access.
Digital Office Group can help businesses manage Microsoft 365 licensing, reduce unnecessary spend and ensure users have the correct licences for email, Teams, SharePoint, OneDrive and security features.
13. Rebuild the Outlook Profile
If Outlook continues to fail after basic checks, the local Outlook profile may be corrupted. Creating a new Outlook profile can often resolve persistent sending, receiving and synchronisation issues.
This should usually be handled carefully, especially where users have multiple mailboxes, shared calendars, archived data or cached accounts.
When Should You Contact IT Support?
You should contact your IT support provider if:
- Several users are affected
- Emails are not arriving across the business
- Outlook keeps asking for passwords
- Emails are bouncing back
- Shared mailboxes are not updating
- You suspect an account has been compromised
- Your DNS records have recently changed
- You are unsure whether the issue is Microsoft 365 or local IT
Email is one of the most critical systems in any business. If Outlook problems are recurring, it may be a sign that your Microsoft 365 environment, security setup, licensing or IT support arrangement needs reviewing.
Microsoft 365 and Outlook Support from Digital Office Group
Digital Office Group provides Microsoft 365 support, managed IT services, cyber security, email protection and business technology support for organisations across Nottingham, Derby, Leicester, the East Midlands and the wider UK.
We can help with:
- Outlook troubleshooting
- Microsoft 365 support
- Exchange Online support
- Email migration
- Mailbox management
- Microsoft 365 licensing
- Multi-factor authentication
- Conditional access
- SPF, DKIM and DMARC setup
- Email security and phishing protection
- Managed IT support
Learn more about our Microsoft 365 services or speak to our team if your business needs reliable Outlook and email support.
Need Help with Outlook or Microsoft 365?
If Outlook is not sending or receiving emails, Digital Office Group can help identify the cause and get your business email working again.
FAQs: Outlook Not Sending or Receiving Emails
Why is Outlook not receiving emails?
Outlook may not receive emails because of internet issues, mailbox storage limits, Microsoft 365 problems, incorrect DNS records, Outlook profile corruption or email rules moving messages to another folder.
Why are my Outlook emails stuck in the outbox?
Emails may get stuck in the outbox if they contain large attachments, the internet connection drops, Outlook is working offline, or the mailbox is unable to connect to Microsoft 365.
Can Microsoft 365 stop Outlook from working?
Yes. Microsoft 365 licensing, authentication, Exchange Online service issues, MFA settings or account security policies can all affect Outlook access.
Why does Outlook keep asking for my password?
This may be caused by expired credentials, a changed password, MFA issues, conditional access settings, account lockout or a corrupted Outlook profile.
Can Digital Office Group support Microsoft 365 and Outlook?
Yes. Digital Office Group supports businesses with Microsoft 365, Outlook, Exchange Online, email security, licensing, migrations and ongoing managed IT support.
Final Thoughts
When Outlook stops sending or receiving emails, it can affect communication, customer service, sales and day-to-day operations. Some issues are simple to fix, but recurring Outlook problems often point to a wider Microsoft 365, security, licensing or network issue.
If your business is experiencing regular Outlook or Microsoft 365 problems, Digital Office Group can review your setup and provide practical support to improve reliability, security and performance.