SMTP Provider Profile Configuration for Bulk Email Dispatch

smtp provider settings illustration

The SMTP Provider Profile Configuration feature allows you to configure email queue processing based on your SMTP provider’s capabilities. This prevents account suspensions, spam flags, and ensures reliable email delivery for bulk email campaigns.

Available in: SMPPCenter v7.6+
User Level: Administrator
Location: Settings → General → E-Mail Settings

What is SMTP Provider Profile Configuration?

When sending bulk emails (newsletters, announcements, user notifications), different SMTP providers have different sending limits and restrictions. Sending emails too quickly or in large batches can result in:

  • ❌ Account suspension (especially Google Workspace)
  • ❌ Spam flags and blacklisting
  • ❌ SMTP connection timeouts
  • ❌ Temporary blocks from email providers

The SMTP Provider Profile system automatically applies the correct rate limits, batch sizes, and connection management settings based on your SMTP provider.

Available Profiles

SMPPCenter includes 5 pre-configured profiles to match your SMTP provider:

1. Google Workspace

  • Best For: Google Workspace / Gmail SMTP users
  • Batch Size: 20 emails per cron run
  • Rate Limit: 1 email every 3 seconds (20 emails/minute)
  • SMTP Reset: Every 10 emails
  • Daily Limit: Compliant with Google’s 2,000 emails/day limit
  • Use When: You’re using Google Workspace SMTP and want to prevent account suspension

2. Standard ⭐ (Default)

  • Best For: Most SMTP providers (shared hosting, cPanel, Plesk)
  • Batch Size: 50 emails per cron run
  • Rate Limit: 2 emails per second (120 emails/minute)
  • SMTP Reset: Every 20 emails
  • Use When: Using standard shared hosting SMTP, Outlook, Yahoo, or similar providers

3. High Volume

  • Best For: Transactional email services (SendGrid, Mailgun, AWS SES, Postmark)
  • Batch Size: 100 emails per cron run
  • Rate Limit: 10 emails per second (600 emails/minute)
  • SMTP Reset: Every 50 emails
  • Use When: You have a paid transactional email service with high sending limits

4. Enterprise

  • Best For: Dedicated SMTP servers, private mail servers
  • Batch Size: 200 emails per cron run
  • Rate Limit: 20 emails per second (1,200 emails/minute)
  • SMTP Reset: Every 100 emails
  • Use When: You control your own mail server with no external restrictions

5. Custom

  • Best For: Advanced users who need fine-tuned control
  • Configuration: Set your own batch size, rate limit, and SMTP reset values
  • Ranges:
  • Max Batch Size: 1-500 emails
  • Rate Limit: 0.1-50 emails/second
  • SMTP Reset: 5-200 emails
  • Use When: You know your SMTP provider’s exact limits and want custom settings
smtp provider settings illustration

How to Configure

Step 1: Access Settings

  1. Log in to your Admin Panel
  2. Navigate to Settings → General
  3. Click on the E-Mail Settings tab
  4. Scroll down to “Bulk E-Mail Dispatch Settings – SMTP Provider Profile”

Step 2: Select Your Profile

  1. Click the “SMTP Provider Profile” dropdown
  2. Select the profile that matches your SMTP provider:
  • Using Google Workspace? → Select “Google Workspace”
  • Using SendGrid/Mailgun/SES? → Select “High Volume”
  • Using shared hosting SMTP? → Select “Standard”
  • Have a dedicated server? → Select “Enterprise”
  • Need custom settings? → Select “Custom”
  1. The “Current Configuration” panel will show you the active settings

Step 3: Configure Custom Settings (Optional)

If you selected “Custom” profile:

  1. The “Custom Configuration” section will appear
  2. Set your values:
  • Max Batch Size: How many emails to send per cron run (1-500)
  • Rate Limit: How many emails per second (0.1-50)
  • SMTP Reset Threshold: Reset SMTP connection after X emails (5-200)

Step 4: Save Changes

  1. Click “Save changes” at the bottom of the page
  2. Your settings are now active and will be used by the email queue cron job

Understanding the Settings

Max Batch Size

  • Number of emails processed in one cron execution
  • Lower values: Safer, prevents overload
  • Higher values: Faster processing (if your SMTP allows)

Rate Limit (emails/second)

  • Speed at which emails are sent
  • Example: 2 emails/sec = 120 emails/minute = 7,200 emails/hour
  • Includes automatic delays between emails to prevent spam flags

SMTP Reset Threshold

  • How often the SMTP connection is reset
  • Prevents timeout errors with remote SMTP servers
  • Example: “Every 20 emails” = after sending 20 emails, pause 2 seconds and reconnect

Monitoring Email Dispatch

Log File Location

All email cron activity is logged in: logs

What Gets Logged

The cron logs detailed information on every execution:

========== SendEmail Cron START ==========
SendEmail Cron CONFIG: Active Profile = STANDARD (Standard (Most SMTP providers))
SendEmail Cron CONFIG: Max Batch Size = 50 emails/run (Admin requested: 200, Profile limit: 50)
SendEmail Cron CONFIG: Rate Limit = 2 emails/second (120 emails/minute)
SendEmail Cron CONFIG: Delay Between Emails = 0.5 seconds
SendEmail Cron CONFIG: SMTP Reset Threshold = Every 20 emails
SendEmail Cron CONFIG: Final Batch Size = 50 emails (will process this batch now)

SendEmail Cron Email sent successfully to: user@example.com | Subject: Welcome to our platform
SendEmail Cron Email sent successfully to: admin@example.com | Subject: Monthly newsletter
SendEmail Cron SMTP connection reset after 20 emails

SendEmail Cron BATCH COMPLETE: Total sent: 50 emails in 27.34 seconds
SendEmail Cron BATCH STATS: Average time per email: 0.55 seconds
SendEmail Cron BATCH STATS: Actual throughput: 109.73 emails/minute
SendEmail Cron CLEANUP: Deleted 50 successfully sent email(s) from queue
========== SendEmail Cron END ==========

Key Metrics to Monitor

  • Total sent: Number of emails successfully delivered
  • Batch duration: How long the batch took
  • Actual throughput: Real emails/minute (compare with profile limit)
  • Failed emails: Any errors (check for SMTP issues)

Relationship with Batch E-Mail Settings

The profile settings work together with your existing “Marketing E-Mail Settings”:

How It Works

  1. Enable Batch E-Mail: Master on/off switch
  2. Batch E-Mail Count: Your desired batch size (e.g., 200 emails)
  3. Profile Limit: Safety limit based on SMTP provider (e.g., 50 emails)
  4. Final Batch Size: System uses the lower value (50 emails)

Example Scenario

Admin Settings:
├─ Enable Batch E-Mail: ✅ Enabled
├─ Batch E-Mail Count: 200 emails
└─ SMTP Provider Profile: Standard (limit: 50 emails)

Result: Cron will send 50 emails per run (safer value)

Why? This ensures safe email dispatch regardless of admin configuration. Even if you request 200 emails, the system won’t exceed your SMTP provider’s safe limits.

Common Use Cases

Scenario 1: Google Workspace Account Getting Suspended

Problem: Your Google Workspace account was suspended for sending too many emails too quickly.

Solution:

  1. Select “Google Workspace” profile
  2. Save settings
  3. Google-safe limits will be applied (20 emails/min)
  4. Your account won’t be flagged anymore

Scenario 2: Using SendGrid for Transactional Emails

Problem: You have a SendGrid account with high sending limits but the system is sending too slowly.

Solution:

  1. Select “High Volume” profile
  2. Save settings
  3. System will now send 600 emails/minute (10 emails/sec)
  4. Full utilization of your SendGrid capacity

Scenario 3: Dedicated Mail Server with Custom Limits

Problem: You have a private mail server with specific limits (e.g., 150 emails/run, 5 emails/sec).

Solution:

  1. Select “Custom” profile
  2. Set Max Batch Size: 150
  3. Set Rate Limit: 5
  4. Set SMTP Reset: 30
  5. Save settings
  6. System uses your exact specifications

Best Practices

✅ Do’s

  • ✅ Start conservative: Use “Standard” or “Google Workspace” profile initially
  • ✅ Monitor logs: Check Log after enabling to verify it’s working
  • ✅ Test with small batches: Send a few emails first to ensure SMTP works
  • ✅ Match your provider: Select the profile that matches your SMTP provider
  • ✅ Use Custom carefully: Only use Custom profile if you know your exact limits

❌ Don’ts

  • ❌ Don’t use Enterprise profile with Google Workspace (will cause suspension)
  • ❌ Don’t set Custom values too high without testing
  • ❌ Don’t ignore failed email logs (indicates SMTP issues)
  • ❌ Don’t change profiles frequently (pick one and stick with it)

Troubleshooting

Problem: Emails Sending Too Slowly

Possible Causes:

  • Profile limit is too conservative for your SMTP

Solutions:

  1. Check your SMTP provider’s actual limits
  2. Select a higher-volume profile if appropriate
  3. Or use Custom profile with higher values

Problem: SMTP Connection Timeouts

Possible Causes:

  • SMTP reset threshold is too high
  • Rate limit is too fast

Solutions:

  1. Lower the SMTP reset threshold (e.g., from 50 to 20)
  2. Reduce rate limit slightly
  3. Check SMTP server logs for connection issues

Problem: Account Suspended/Blocked

Possible Causes:

  • Profile is too aggressive for your SMTP provider
  • Sending too many emails per day

Solutions:

  1. Switch to “Google Workspace” or “Standard” profile
  2. Contact your SMTP provider to confirm daily limits
  3. Reduce batch email count in Marketing E-Mail Settings
  4. Space out cron executions (e.g., every 10 minutes instead of 5)

Problem: Custom Settings Not Working

Possible Causes:

  • Custom values outside allowed ranges
  • Validation errors not shown

Solutions:

  1. Verify values are within ranges:
  • Max Batch: 1-500
  • Rate Limit: 0.1-50
  • SMTP Reset: 5-200
  1. Check for error messages after saving
  2. Revert to a pre-configured profile first

Cron Schedule Recommendations

Based on your profile, here are recommended cron schedules:

Google Workspace Profile

*/5 * * * * # Every 5 minutes
# Sends: 20 emails × 12 runs/hour = 240 emails/hour = 5,760 emails/day

Standard Profile

*/5 * * * * # Every 5 minutes
# Sends: 50 emails × 12 runs/hour = 600 emails/hour = 14,400 emails/day

High Volume Profile

*/2 * * * * # Every 2 minutes
# Sends: 100 emails × 30 runs/hour = 3,000 emails/hour = 72,000 emails/day

Enterprise Profile

* * * * * # Every minute
# Sends: 200 emails × 60 runs/hour = 12,000 emails/hour = 288,000 emails/day

FAQ

Q: Will changing the profile affect emails already in queue?

A: No. Emails remain in queue and will be processed with the new profile settings on the next cron run.

Q: Can I switch profiles at any time?

A: Yes. Changes take effect immediately for the next cron execution.

Q: What happens if I don’t configure this?

A: The system defaults to “Standard” profile (50 emails/run, 2 emails/sec) which is safe for most SMTP providers.

Q: Does this affect transactional emails (password resets, etc.)?

A: No. This only affects bulk email campaigns sent via the Marketing → Send E-Mail feature. Transactional emails are sent immediately.

Q: How do I know which profile to choose?

A: Check your SMTP provider’s documentation:

  • Google Workspace: 2,000 emails/day → Use “Google Workspace” profile
  • SendGrid Free: 100 emails/day → Use “Standard” profile
  • SendGrid Paid: 40,000+ emails/day → Use “High Volume” profile
  • Private Server: No limits → Use “Enterprise” or “Custom” profile

Q: Can I see the current profile in the logs?

A: Yes. Every cron execution logs the active profile and all configuration details at the start.

Support

If you need assistance configuring SMTP Provider Profiles:

Last Updated: Version 7.6

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