Emails Not Delivering

If customers aren't receiving back-in-stock notification emails, follow this systematic guide to diagnose and fix delivery issues.

What you'll accomplish

• Diagnose why notification emails are not being delivered
• Fix queue, authentication, spam, and bounce issues
• Verify email delivery with test sends and log analysis
• Prevent future deliverability problems with monitoring best practices

Quick Diagnostic Questions

Answer these to narrow down the problem:

1. Are ANY emails being delivered? (Some vs None)
2. Are emails going to spam/junk folders?
3. Do test emails work?
4. Is the queue paused or active?
5. Are emails showing as "sent" in Dashboard?

Based on answers, jump to relevant section below.

---

Check Email Delivery Status

Dashboard → Notifications → History

Step 1: View recent sends

Dashboard → Notifications → History tab
→ Shows last 100 email notifications

Step 2: Check status column

Successful delivery:

Status: DeliveredSent: 2 minutes ago
Customer: [email protected]
Product: Nike Shoes - Size 10

Failed delivery:

Status: FailedError: Invalid email address
Sent: 5 minutes ago
Customer: invalid@@email

Pending/queued:

Status: QueuedPosition: 23 in queue
Expected: 45 minutes

Understanding Status Types

"Delivered"

• Email successfully sent to recipient's mail server
• Does NOT guarantee inbox delivery
• May still land in spam folder

"Failed"

• Email rejected by recipient's server
• Common reasons: Invalid address, blocked domain
• Customer won't receive notification

"Bounced"

• Email returned by recipient's server
• Soft bounce: Temporary issue (mailbox full)
• Hard bounce: Permanent failure (email doesn't exist)

"Queued"

• Waiting to send (Fair Queue batching)
• Normal status, will send soon
• Check queue settings if too slow

---

Problem 1: No Emails Sending At All

Check Queue Status

Dashboard → Notifications → Queue Status

Normal status:

Queue: ActivePending notifications: 23
Next batch: 15 minutes

Paused queue:

Queue: PausedReason: Manual pause
Pending: 47 notifications waiting
Action: Resume queue

Issue: Queue manually paused

Fix:

Dashboard → Notifications → Queue Status
→ Click "Resume Queue"
→ Notifications start sending immediately

Issue: Free plan limit reached

Fix:

Dashboard → Overview
→ Check: "Email notifications: 500/500"
→ Options:
  1. Wait until next month (resets 1st)
  2. Upgrade to Growth (unlimited)

See Plan Limits & Upgrades for details.

Check Email Service Integration

Dashboard → Settings → Email Integration

Healthy status:

Email provider: Resend
Status: ConnectedLast test: 2 hours ago
Success rate: 98.7%

Connection issue:

Email provider: Resend
Status: DisconnectedLast successful send: 3 days ago
Action needed: Reconnect service

If disconnected:

1. Click "Reconnect email service"
2. Authorize Resend connection
3. Send test email
4. Verify test arrives

Check System Health

Dashboard → Settings → Health Checks

Look for warnings:

Email service health:

Resend API: Operational
DNS records: Valid
Sending quota: 95% available
Bounce rate: 2.1% (normal)

Red flags:

Resend API: Rate limit exceeded
DNS records: SPF missing
Sending quota: 0% available
Bounce rate: 45% (critical)

If API rate limited:

• Temporary service slowdown
• Emails queued, will send when quota resets
• Usually resolves within 1 hour
• Contact support if persists > 24 hours

---

Problem 2: Emails Going to Spam

Why Emails Land in Spam

Common causes:

1. Domain reputation issues

• New domain (no sending history)
• Previous spam complaints
• Low engagement rates

2. Missing authentication

• SPF record not configured
• DKIM signature missing
• DMARC policy absent

3. Content triggers

• Spammy subject lines
• Too many links
• ALL CAPS text
• Excessive punctuation!!!

4. Recipient behavior

• Customer marked previous email as spam
• Low email engagement historically
• Inactive email address

Check Email Authentication

Dashboard → Settings → Email Authentication

Properly configured:

SPF Record: Valid
DKIM Signature: Signing emails
DMARC Policy: Configured
Domain: demandloop.metigro.io
Status: All checks passing

Configuration issues:

SPF Record: Not found
DKIM Signature: Not verified
DMARC Policy: Missing
Action: Configure DNS records

Configure DNS Records (Advanced)

If you have custom domain (custom-domain.com):

Step 1: Get DNS records

Dashboard → Settings → Email Authentication
→ Click "Setup custom domain"
→ Copy provided DNS records

Step 2: Add to DNS provider

SPF Record:

Type: TXT
Host: @
Value: v=spf1 include:resend.com ~all
TTL: 3600

DKIM Record:

Type: TXT
Host: resend._domainkey
Value: [provided by DemandLoop]
TTL: 3600

DMARC Record:

Type: TXT
Host: _dmarc
Value: v=DMARC1; p=none; rua=mailto:[email protected]
TTL: 3600

Step 3: Verify in Dashboard

Dashboard → Settings → Email Authentication
→ Click "Verify DNS records"
→ Wait 24-48 hours for propagation
→ Should show all```

**Note:** DNS changes can take 24-48 hours to propagate globally.

### Improve Email Content

**Subject line best practices:**

**Good examples:**

"Nike Air Max - Back in Stock!" "Your requested item is available" "Size 10 restocked - order now"

**Spam-triggering examples:**

"BUY NOW!!! HURRY!!!" "FREE SHIPPING - CLICK HERE" "You won a prize! Open immediately!"

**Customize in Dashboard:**

Dashboard → Settings → Email Templates → Edit subject line → Avoid: ALL CAPS, excessive !!!, "free", "buy now" → Use: Product name, simple call-to-action

### Test Spam Score

**Use mail-tester.com:**

**Step 1: Send test email**

Dashboard → Settings → Email Testing → Click "Send test email" → Enter: [email protected]

**Step 2: Check score**

Visit: https://www.mail-tester.com → View your score (aim for 8+/10) → Read specific recommendations → Fix flagged issues

**Common issues flagged:**
- Missing authentication records
- Poor sender reputation
- Spammy content detected
- Broken links
- Image-heavy email

---

## Problem 3: Emails Delayed

### Check Fair Queue Settings

**Dashboard → Settings → Fair Queue**

**Current settings:**

Batch size: 50 emails Batch delay: 2 hours Rate: ~25 emails/hour

**If delays too long:**

**Increase send rate:**

Batch size: 100 emails (from 50) Batch delay: 1 hour (from 2 hours) New rate: ~100 emails/hour

**Trade-off:**
- Faster sending = less "fair" (first subscribers notified first)
- Slower sending = more "fair" (everyone gets chance)

See [Fair Queue Settings](/help-center/notifications/fair-queue) for strategy.

### Check Email Queue

**Dashboard → Notifications → Queue Status**

**Heavy backlog:**

Pending notifications: 347 Current position: 147 in queue Estimated wait: 6 hours

**If backlog too large:**

**Option 1: Increase send rate**
- Adjust Fair Queue settings (above)
- Temporarily increase batch size
- Reset to normal after catching up

**Option 2: Upgrade plan**
- Growth plan has higher sending capacity
- No artificial delays
- Faster infrastructure

**Option 3: Prioritize products**

Dashboard → Settings → Product Priorities → Disable notifications for low-priority items → Focus on high-value products → Reduces queue size

---

## Problem 4: Specific Email Addresses Failing

### Check Bounce List

**Dashboard → Notifications → Bounced Emails**

**Hard bounces (permanent):**

Email: [email protected] (should be gmail) Reason: Domain doesn't exist Status: Permanently failed Action: Customer must resubscribe with correct email

**Soft bounces (temporary):**

Email: [email protected] Reason: Mailbox full Status: Will retry 3 times Action: Wait for retry or customer clears inbox

### Retry Failed Emails

**Soft bounces retry automatically:**

Attempt 1: Failed (mailbox full) Wait: 1 hour Attempt 2: Failed (still full) Wait: 6 hours Attempt 3: Success```

Manual retry:

Dashboard → Notifications → History
→ Find failed email
→ Click "Retry"
→ Attempts immediate resend

Unsubscribed Emails

Check unsubscribe list:

Dashboard → Subscriptions → Unsubscribed
→ Search customer email

If customer unsubscribed:

• Emails won't send (legal requirement)
• Customer must resubscribe via widget
• Can't manually re-add them

If wrongly unsubscribed:

1. Verify customer wants emails
2. Ask customer to resubscribe via website
3. Or Dashboard → Subscriptions → Reactivate
   (only with customer's explicit consent)

---

Problem 5: Emails Delivered But Not Received

Common Recipient Issues

1. Spam/junk folder

Ask customer to check:

Gmail: Check "Spam" folder
Outlook: Check "Junk Email" folder
Yahoo: Check "Bulk" folder
Apple Mail: Check "Junk" mailbox

If found in spam:

1. Customer marks as "Not Spam"
2. Adds sender to contacts/safe list
3. Future emails deliver to inbox```

**2. Email filters/rules**

Some customers have filters that auto-delete/move emails.

**Ask customer to check:**

Email settings → Filters/Rules → Look for rules moving "no-reply@" emails → Disable or adjust filter → Add exception for demandloop domain

**3. Aggressive corporate filters**

Enterprise email systems (Microsoft Exchange, Google Workspace) may block external notifications.

**Solutions:**
- Customer asks IT to whitelist demandloop.metigro.io
- Customer uses personal email instead
- Customer checks quarantined emails

**4. Email forwarding issues**

If customer forwards notifications to another address:
- Original may get filtered
- Forwarded email may lose formatting
- Tracking may break

**Fix:**
- Subscribe with final email directly
- Don't rely on forwarding

---

## Testing Email Delivery

### Send Test Email

**Dashboard → Settings → Email Testing**

**Step 1: Enter test email**

Your email: [email protected] → Click "Send Test Notification"

**Step 2: Check inbox (within 1 minute)**

**What to verify:**
- Email arrives in inbox (not spam)
- Subject line renders correctly
- Product link works
- Unsubscribe link works
- Images load (if any)

**Step 3: Test multiple providers**

Send tests to:

• Gmail account
• Outlook account
• Yahoo account
• Corporate email (if applicable)

Different providers have different spam filters.

### Check Email Logs

**Dashboard → Settings → Email Logs**

**Detailed delivery timeline:**

12:00:00 - Email queued 12:00:15 - Sent to Resend API 12:00:18 - Accepted by API 12:00:22 - Delivered to recipient server 12:00:25 - Inbox placement confirmed```

Look for errors:

12:00:00 - Email queued
12:00:15 - Sent to Resend API
12:00:18 - Rejected by APIError: "Recipient email blocked due to previous bounces"

---

Email Provider Issues

Resend API Status

Check service status:

Visit: https://status.resend.com
→ All systems operational```

**If Resend has issues:**
- Emails automatically queued
- Will retry when service restored
- No action needed on your end

**Dashboard shows:**

Email service degraded Notifications queued for later delivery Estimated resolution: 2 hours

### Rate Limits

**Free tier limits (rare issue):**

Resend free tier: 100 emails/day If exceeded: Emails queue until next day Upgrade: Growth plan uses paid Resend tier

**Check current usage:**

Dashboard → Settings → Email Quota → Shows: 87/100 emails today → Resets: Tomorrow at midnight UTC

**If hitting limit:**
- Upgrade to Growth (unlimited)
- Or spread notifications across multiple days
- Or adjust Fair Queue to send slower

---

## Advanced Diagnostics

### Email Headers Analysis

**For technical users:**

**Step 1: Get email source**

Gmail: Open email → Three dots → "Show original" Outlook: Open email → File → Properties Yahoo: Open email → More → "View raw message"

**Step 2: Check SPF/DKIM results**

**Look for:**

Authentication-Results: spf=pass; dkim=pass; dmarc=pass```

Issues:

Authentication-Results: spf=fail→ SPF record not configured or incorrect

Authentication-Results: dkim=neutral→ DKIM signature missing or invalid

Step 3: Check delivery path

Received: headers show email journey
→ From: demandloop.metigro.io
→ Through: resend.com
→ To: recipient's mail server
→ Each hop should be < 1 second

Long delays indicate:

• Greylisting (recipient server delaying)
• Spam analysis in progress
• Server issues

SMTP Responses

Email logs show SMTP codes:

Success codes:

250 OK - Message accepted```

**Temporary failures:**

421 - Service not available (try again later) 450 - Mailbox unavailable (mailbox full) 451 - Server error (temporary issue)

**Permanent failures:**

550 - Mailbox not found (email doesn't exist) 551 - User not local (forwarding failed) 554 - Message rejected (spam/policy violation)

**If seeing persistent 5xx errors:**
- Contact support with SMTP logs
- May indicate domain blacklist
- Requires investigation

---

## Common Scenarios & Solutions

### Scenario 1: Worked Before, Stopped Now

**Likely causes:**
- Queue manually paused
- Email service disconnected
- DNS records expired
- Plan limit reached

**Fix:**

1. Check queue status (Dashboard → Notifications)
2. Verify email integration (Dashboard → Settings)
3. Check DNS records (Dashboard → Email Auth)
4. Review usage limits (Dashboard → Overview)

### Scenario 2: Some Customers Get Emails, Others Don't

**Likely causes:**
- Email provider differences (Gmail works, Yahoo doesn't)
- Some customers' addresses bouncing
- Spam filter variance

**Fix:**

1. Check bounce list for failing addresses
2. Send test to failing provider type
3. Improve email authentication
4. Review spam score (mail-tester.com)

### Scenario 3: Test Emails Work, Real Ones Don't

**Likely causes:**
- Queue settings prevent real emails
- Test emails bypass queue
- Fair Queue delay too long

**Fix:**

1. Check Fair Queue settings
2. Reduce batch delay
3. Verify queue not paused
4. Check pending notifications count

### Scenario 4: Emails Arrive Hours Late

**Expected behavior:**
- Fair Queue intentionally delays emails
- Ensures fair distribution
- Not a bug, it's a feature

**If too slow:**

Dashboard → Settings → Fair Queue → Reduce batch delay (2 hours → 30 minutes) → Increase batch size (50 → 100) → Faster delivery (less fair)

See [Fair Queue Settings](/help-center/notifications/fair-queue) for strategy.

---

## Prevention Tips

### Regular Monitoring

**Weekly checks:**

□ Review email delivery rate (Dashboard → Analytics) □ Check bounce rate (aim for < 5%) □ Monitor spam complaints (aim for < 0.1%) □ Verify queue not backed up

**Monthly maintenance:**

□ Clean bounce list (remove old hard bounces) □ Review email template performance □ Check DNS records still valid □ Test across major email providers

### Best Practices

**1. Keep email list clean**

• Remove persistent hard bounces
• Don't import old/stale email lists
• Only collect opt-in subscriptions

**2. Maintain sender reputation**

• Keep spam complaints low
• Respond to unsubscribes quickly
• Never send to purchased lists
• Honor opt-outs immediately

**3. Monitor metrics**

Dashboard → Analytics → Email Performance → Track:

• Delivery rate (aim for > 95%)
• Open rate (aim for > 20%)
• Click rate (aim for > 5%)
• Bounce rate (aim for < 5%)

**4. Test before major changes**

Before changing:

• Email templates
• DNS settings
• Domain configurations → Send tests to multiple providers → Verify delivery before going live

---

## When to Contact Support

Contact [email protected] if:

**1. Widespread delivery failure**
- No emails delivering for > 6 hours
- All recipients affected
- Queue active but nothing sending

**2. Persistent authentication issues**
- DNS records configured correctly
- Still failing SPF/DKIM checks
- 48+ hours since DNS changes

**3. Unexpected bounces**
- Valid emails bouncing
- Same customer email bounced 3+ times
- Bounce reason unclear

**4. Service integration broken**
- Can't reconnect email service
- API errors persisting > 24 hours
- Health checks showing ongoing issues

**5. Spam problem not resolving**
- Followed all spam fixes
- Still landing in spam folder
- Mail-tester score < 5/10

### Information to Include

Shop domain Example email addresses affected Email delivery logs (Dashboard → Logs) Screenshots of errors When issue started Recent changes (DNS, templates, settings) Test email results

---

## Additional Resources

- **Email templates guide:** [Customizing Email Templates](/help-center/notifications/email-templates)
- **Fair Queue explained:** [Fair Queue Settings](/help-center/notifications/fair-queue)
- **Notification flow:** [How Notifications Work](/help-center/notifications/how-notifications-work)

**Still experiencing issues?**

Email [email protected] with:
- Detailed description
- Affected customer emails
- Delivery logs/screenshots

We'll diagnose and resolve within 24 hours.