Debugging Common Email Delivery Issues

Common Issues and Solutions#

1. Emails Going to Spam#

Symptoms: Low open rates, subscribers report emails in spam folder.

Checklist:

• SPF record configured correctly
• DKIM signing active
• DMARC policy set
• Sending from authenticated domain (not gmail.com)
• Content not triggering spam filters
• IP/domain not on any blacklists
• Consistent sending volume (no sudden spikes)

Diagnosis:

# Check blacklists
# Visit: https://mxtoolbox.com/blacklists.aspx

# Check authentication
# Visit: https://www.mail-tester.com/
# Send a test email to the provided address

# Check Google reputation
# Visit: https://postmaster.google.com/

2. High Bounce Rate#

Symptoms: Bounce rate above 2%, delivery failures.

Common Causes:

• Old/stale email list
• Purchased or scraped lists (never do this)
• Typos in email addresses
• Temporary server issues (soft bounces)

Solutions:

• Enable email verification before import
• Remove hard bounces immediately
• Re-confirm old lists before sending
• Use double opt-in for all new subscribers

3. Emails Not Sending#

Symptoms: Campaign stuck in "sending" status, queue not processing.

Debug Steps:

# Check queue workers
sudo supervisorctl status

# Check failed jobs
php artisan queue:failed

# Check sending server connection
php artisan tinker
>>> Mail::raw('Test', function($m) { $m->to('test@test.com'); });

# Check logs
tail -f storage/logs/laravel.log

4. Slow Sending Speed#

Symptoms: Large campaigns take hours to complete.

Solutions:

• Increase queue workers (numprocs=4 in supervisor)
• Use Redis instead of database queue driver
• Check sending server rate limits
• Configure multiple sending servers with rotation

5. Images Not Loading in Emails#

Symptoms: Broken image icons in received emails.

Causes:

• Images hosted on HTTP (not HTTPS)
• Server blocking hotlinking
• Images too large (timeout)

Solutions:

• Always use HTTPS URLs for images
• Host images on your server or CDN
• Optimize image file sizes (under 200KB each)
• Use alt text for all images