Outlook: Can't Send Emails — Error or Stuck in Outbox

If emails are sitting in your Outbox and not sending, or you're getting an error when trying to send, work through these steps. Step 1: Check if you're online Make sure Outlook shows "Connected to Microsoft Exchange" or "Connected" in the bottom status bar. If it says "Offline," go to Send/Receive > uncheck "Work Offline." Step 2: Delete the stuck email and resend Open your Outbox folder. If there's a large attachment, Outlook may be stuck trying to send it. Open the email, remove the attachment, save it to drafts, and resend without the oversized attachment. Microsoft 365 has a 25MB attachment limit by default. Step 3: Check for send/receive errors Go to Send/Receive tab > Show Progress. This will display any errors happening during sync. Step 4: Repair your account Go to File > Account Settings > Account Settings. Select your account and click Repair. Let the wizard complete. Step 5: Check your email quota If your mailbox is full, you may not be able to send or receive. Go to File > Info and check mailbox usage. Contact us to increase storage if needed. Step 6: Test sending via Outlook on the Web Go to outlook.office.com and log in with your work email. Try sending an email from there. If it works from the web but not from the desktop app, the issue is with your local Outlook installation — reinstalling or running SaRA will fix it. Still stuck? Call us at (269) 261-0269.