TABLE OF CONTENTS

• What's Happening?
• Quick Diagnosis: Identifying Rate Limiting Issues
• Understanding Rate Limiting and Throttling
• Step-by-Step Rate Limiting Resolution
• Recovery Timeline and Expectations
• Prevention Best Practices
• Still Having Issues?

Rate Limited/Throttled Email Delivery: Complete Resolution Guide

What's Happening?

Your emails are being temporarily delayed or rejected because recipient servers are limiting the rate at which they accept messages from your sending domain or IP address. This is a protective measure that email providers use to prevent spam and manage server load, but it can affect legitimate senders when volume spikes or reputation drops.

Quick Diagnosis: Identifying Rate Limiting Issues

Common Rate Limiting Bounce Messages

• "The recipient's server is temporarily limiting or delaying incoming messages due to high volume or policy"
• "The sending server is temporarily restricted due to high volume or low reputation"
• "The recipient is receiving too many emails too quickly, so further messages are temporarily blocked"
• "Yahoo is temporarily deferring messages due to high volume or user complaints"
• "The recipient's mailbox has reached its hourly message receiving limit"
• "The receiving server delayed or rejected the message due to too many delivery attempts"
• "The recipient server is temporarily limiting or rejecting messages due to high sending volume"
• "The sending server is temporarily deferring messages due to high volume or user complaints"

Understanding Rate Limiting and Throttling

Key Concepts

Rate Limiting Categories

Step-by-Step Rate Limiting Resolution

Step 1: Implement Batch Sending Strategy

Use batch sending feature to control email volume:

1. Access Campaign Creation:
   • Go to Marketing → Campaigns → Create Campaign
   • Select Email Campaign type
   • Choose your email template and audience
2. Configure Batch Sending:
   • In the campaign setup, look for Scheduling Options
   • Select Batch Sending or Schedule in Batches
   • Set conservative batch sizes: Start with 50-100 emails per batch
   • Space batches 2-4 hours apart initially
3. Pause Existing High-Volume Campaigns:
   • Navigate to active campaigns and pause any sending large volumes
   • Convert them to batch sending format
   • Prioritize essential communications only

Step 2: Monitor External Reputation Metrics

Since our patform doesn't provide built-in reputation monitoring, use these external tools:

1. Check Sender Score:
   • Visit senderscore.org
   • Enter your sending domain or IP address
   • Score below 70 indicates reputation issues contributing to rate limiting
2. Verify IP Reputation:
   • Use mxtoolbox.com/blacklists.aspx
   • Check if your sending IP appears on any blacklists
   • Monitor for "policy" or "reputation" related listings
3. Provider-Specific Tools:
   • Gmail: Check Google Postmaster Tools for reputation data
   • Microsoft: Review Smart Network Data Services (SNDS)
   • Yahoo: Monitor Yahoo Sender Hub feedback

Step 3: Leverage Automatic Bounce Handling

Our platform automatically manages bounced addresses to improve your sender reputation:

1. Review Bounce Reports:
   • Go to Marketing → Email → Reports
   • Check bounce rates and types in your recent campaigns
   • Note that hard bounces are automatically marked as invalid
2. Verify Invalid Contact Management:
   • Navigate to Contacts → All Contacts
   • Filter by Invalid or Bounced status
   • Confirm these contacts are excluded from future campaigns
3. Focus on Engaged Segments:
   • Go to Contacts → Smart Lists
   • Create segments based on recent email engagement
   • Prioritize batch sending to your most engaged contacts first

Step 4: Verify Sending Domain Authentication

Ensure proper domain authentication to improve reputation:

1. Check Domain Settings:
   • Go to Settings → Email Services → Sending Domain
   • Confirm SPF, DKIM, and DMARC records show as verified
   • Look for green checkmarks or "Verified" status
2. Update DNS Records if Needed:
   • Copy any unverified DNS records
   • Add them to your domain's DNS settings
   • Wait 24-48 hours for propagation and re-verification

Recovery Timeline and Expectations

Phase 1: Immediate Relief (2-6 hours)

• Action: Switch to batch sending with conservative volumes
• Expected outcome: Reduced bounce rates, fewer "too quickly" messages
• Success metric: 50% reduction in rate limiting bounces

Phase 2: Short-term Stabilization (1-3 days)

• Action: Gradually increase batch sizes with engaged contacts
• Expected outcome: Consistent delivery within each batch
• Success metric: 80%+ delivery rate to high-engagement segments

Phase 3: Full Recovery (1-2 weeks)

• Action: Return to larger batch sizes with reputation monitoring
• Expected outcome: Normal delivery rates across all segments
• Success metric: Less than 2% rate limiting bounces

Prevention Best Practices

Smart Batch Management

• Conservative Start: Begin with small batches (50-100 emails) and increase gradually
• Consistent Timing: Space batches evenly throughout business hours
• Provider Awareness: Consider smaller batches for strict providers like Yahoo
• Engagement Priority: Send to most engaged contacts first in each batch

Ongoing Reputation Maintenance

• Weekly Monitoring: Check sender score and blacklist status weekly
• Bounce Rate Tracking: Monitor bounce rates in campaign reports
• Trust our System: Let automatic bounce handling maintain list quality
• Content Quality: Avoid spam trigger words and maintain professional formatting

Still Having Issues?

If you continue to experience rate limiting challenges after implementing batch sending:

1. Reduce Batch Sizes Further: Try 25-50 emails per batch with longer intervals
2. Segment by Provider: Create separate batches for Gmail, Yahoo, and Outlook recipients
3. Review Content: Analyze email content for elements that might trigger aggressive filtering
4. Consider Timing: Avoid peak sending times when providers are most restrictive