Summary

This guide helps you troubleshoot and resolve: Email not sending or receiving. Follow the steps below to fix the issue.

Common Causes

Quick Checks (Do These First)

Before diving into detailed troubleshooting, run through these quick checks:

1. Check your internet connection — try loading a website in your browser.
2. Check your spam/junk folder — incoming emails may be filtered.
3. Check the email address — confirm you are using the correct address.
4. Check whether you are replying or composing — make sure you are in the correct mode (Reply, Reply All, or New Message).

For Outlook Desktop App

Not Receiving Emails

1. Check send/receive settings:
   • Click Send/Receive > Check for New Messages.
   • Confirm your account is enabled for send/receive.
2. Check Work Offline mode:
   • If the status bar at the bottom-left shows "Working Offline," click it and select Work Online.
3. Repair the account:
   • Go to File > Account Settings > Account Settings.
   • Select your email account and click Repair.
   • Follow the prompts to complete the repair.

Not Sending Emails

1. Check the Outbox:
   • Open the Outbox folder.
   • Double-click any stuck email and try sending it again.
2. Check account settings:
   • Go to File > Account Settings > Account Settings.
   • Verify the email address and server settings are correct.
   • Ensure My outgoing server (SMTP) requires authentication is ticked.
3. Check your password:
   • You may need to re-enter your password.
   • Go to File > Account Settings > Account Settings > Change.
4. Check your mailbox size:
   • Go to File > Account Settings — your mailbox size is shown next to your account.
   • If your mailbox is full, you will not be able to send or receive new emails. Archive or delete old items to free up space.
5. Check inbox rules:
   • Go to File > Manage Rules & Alerts.
   • Review any rules that may be moving, deleting, or forwarding incoming messages automatically.

SMTP and IMAP Port Settings

If you are configuring an email account manually or verifying server settings, use the following port information. Australian ISPs and many corporate networks commonly block port 25 for outgoing mail.

Provider	Incoming (IMAP)	Outgoing (SMTP)
Gmail	imap.gmail.com — Port 993 (SSL/TLS)	smtp.gmail.com — Port 587 (STARTTLS) or 465 (SSL/TLS)
Outlook.com / Microsoft 365	outlook.office365.com — Port 993 (SSL/TLS)	smtp.office365.com — Port 587 (STARTTLS)
Yahoo Mail	imap.mail.yahoo.com — Port 993 (SSL/TLS)	smtp.mail.yahoo.com — Port 465 (SSL/TLS) or 587 (STARTTLS)
Telstra / Optus / TPG / iiNet	Check your ISP welcome email or support portal	Port 25 is often blocked. Use port 587 or 465 instead.

For Outlook for Mac

Not Receiving Emails

1. Check Work Offline mode:
   • Go to Outlook > Work Offline and ensure it is not ticked.
2. Run the Microsoft Outlook for Mac Database Utility:
   • Close Outlook.
   • Hold the Option key and click the Outlook icon in the Dock.
   • Select Rebuild to repair the Outlook identity database.

Not Sending Emails

1. Check the Outbox:
   • Open the Outbox folder.
   • Double-click any stuck email and try sending it again.
2. Verify account settings:
   • Go to Outlook > Settings > Accounts.
   • Select your account and verify the incoming and outgoing server details.
   • Ensure Use SSL to connect is enabled for both IMAP and SMTP.

For Webmail (Gmail, Outlook.com, Yahoo)

Log into the web version of your email provider (for example, mail.google.com, outlook.com, or mail.yahoo.com):

• If emails work in webmail, the issue is with your desktop app or device.
• If emails do not work in webmail either, the issue is with your account or the provider.

Two-Factor Authentication and App Passwords

Modern email accounts often block standard password authentication when two-factor authentication (2FA) is enabled. If your email client prompts for a password repeatedly or rejects your correct password, you may need to generate an app password.

• Gmail: Go to your Google Account > Security > 2-Step Verification > App passwords. Generate a new app password for Mail and use it in Outlook instead of your regular Google password.
• Outlook.com / Microsoft 365: Go to your Microsoft Account > Security > Advanced security options > App passwords. Create a new app password and use it in your email client.
• Yahoo: Go to Account Security > App passwords. Generate an app password for your email application.

Check Provider Status Pages

Check the official status page for your email provider directly, rather than relying only on third-party sites:

• Gmail: Google Workspace Status Dashboard
• Outlook.com / Microsoft 365: Microsoft 365 Service Health
• Yahoo: Yahoo Status

General Troubleshooting

Empty the Auto-Complete List (Outlook)

The Auto-Complete list stores cached email addresses you have typed previously. Clearing it can resolve issues with sending to or auto-completing addresses:

1. Go to File > Options > Mail.
2. Under Send messages, click Empty Auto-Complete List.
3. Click Yes to confirm.

Clear Outlook Temp Files

1. Close Outlook completely.
2. Navigate to C:\Users\[Name]\AppData\Local\Microsoft\Outlook.
3. Delete any temporary files (typically files beginning with ~ or with the .tmp extension).
4. Reopen Outlook.

Check Account Lock Status

If you have entered your password incorrectly multiple times, your email provider may have temporarily locked your account.

• Try logging in to your email provider's webmail directly.
• If you are prompted to reset your password or verify your identity, follow the on-screen steps to unlock your account.
• Wait at least 15–30 minutes after a lockout before attempting to reconnect your email client.

Update Outlook

For Microsoft 365 versions of Outlook:

1. Open Outlook.
2. Go to File > Office Account.
3. Click Update Options > Update Now.

For Outlook 2016 or 2019 (LTSC), updates are managed through Windows Update rather than inside Outlook.

Try Outlook in Safe Mode

Safe Mode opens Outlook without add-ins, which helps identify whether an add-in is causing the issue:

1. Close Outlook.
2. Hold the Ctrl key and click the Outlook shortcut to open it.
3. When prompted, click Yes to start in Safe Mode.
4. Test whether the issue still occurs.

Test on a Different Network

Try connecting from a different network (for example, a mobile hotspot) to rule out local network or firewall issues blocking SMTP or IMAP ports.

Check Antivirus and Firewall

Some antivirus or firewall applications can block Outlook from connecting to mail servers. Temporarily disable your security software to test, or add Outlook to its allowlist.

Check Custom Domain DNS and MX Records

If you use a custom domain for email (for example, [email protected]), email delivery issues may be caused by incorrect DNS or MX records.

• Use an online DNS lookup tool to check your domain's MX records.
• Confirm the MX records point to your email provider's mail servers.
• If you recently changed hosting or email providers, DNS changes can take up to 48 hours to propagate.
• Contact your domain registrar or IT administrator if the records appear incorrect.

When to Escalate

Open a support ticket with us if:

• You have tried the steps above and the issue persists.
• You are receiving specific error codes you cannot resolve.
• Your account may be disabled, suspended, or compromised.
• You suspect a server-side issue affecting multiple users.

When raising a ticket, please include the following information to help us resolve your issue faster:

• The full text of any error codes or bounce-back messages.
• Screenshots of the error or the affected email client window.
• Steps you have already tried from this guide.
• Whether the issue occurs in webmail, Outlook desktop, or both.
• Your email address and the domain name (if using a custom domain).

For password resets or account lockouts, contact your email provider directly (for example, Google, Microsoft, or Yahoo) before raising a ticket.

Open a Ticket

Related Articles

• Email delivery failed (NDR)
• Email delivery delays
• Setting Up an Email Account in Outlook (POP/IMAP/Exchange)
• How to add email to Outlook
• Deleted email recovery

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