❌ "No errors and nothing sent"

• Missing Subject: Did you enter a subject line? (Required)
• No CSV selected: Make sure CSV file is selected before sending
• CSV headers wrong: First row must be: Email,FirstName,LastName
• SMTP not configured: Check ⚙️ SMTP Config tab
• SMTP auth failed: Click "Test Connection" button to verify
• All emails unsubscribed: Check 📧 Email History tab
• All emails invalid: Check CSV format (must be valid emails)

📝 Debugging Steps

1. Open browser DevTools (F12) → Network tab
2. Send test campaign
3. Check response from api/send_emails.php
4. Look for error messages in "debug" field
5. Verify all fields filled (campaign name, subject, CSV, HTML)

✉️ SMTP Connection Issues

• Go to ⚙️ SMTP Config
• Click "🔗 Test Connection" button
• If it fails, check:
  • Host: smtp.gmail.com (for Gmail)
  • Port: 587 (TLS) or 465 (SSL)
  • Username: Your full email address
  • Password: App password (not regular password)