Cannot send mail

1. Quick Check
Network Connection
Confirm network is working (try to access web pages)
Turn off VPN/firewall temporary test
Outbox Status
Check Inbox for stuck messages
Right click on Outbox > “Empty Folder” (if emails are not important)
2. Account Settings Repair
 Re-verify account
File > Account Settings > Select Account > “Repair”
Follow the wizard (password required)
Manually configure SMTP
Account Settings > Double-click on the account > “Other Settings”
Switch to the “Outgoing Servers” tab
Check “My sending server requires authentication”
Select “Use the same settings as the receiving server”
3. Mail formatting issues
To reduce the message format
New Message > Switch to “Plain Text” format (Options > Format)
Test Send
 Remove large attachments
Compress attachments (keep single message ≤ 20MB)
Switch to OneDrive shared links
4. Advanced Repair
Reset Outlook Configuration
Close Outlook
Delete the profile (proceed with caution):
Control Panel > Mail > Show Profiles > Delete Current Configuration
Re-add accounts
Check COM Add-ons
File > Options > Add-ons
Select “COM Add-ons” at the bottom > “Go To”
Uncheck all add-ins > Restart Outlook