If your Noptin email campaigns are not sending, or are only reaching some of your subscribers, you’re not alone. Email delivery issues can be caused by a number of factors, from server limitations to misconfiguration.
This guide provides a comprehensive troubleshooting process to help you identify and resolve the most common email delivery problems in WordPress and Noptin.
1. Confirm the Problem
Before diving into complex diagnostics, confirm the issue:
- Are emails not sending at all?
- Are only a portion of subscribers receiving them?
- Are emails being sent but not being received?
- Is Noptin taking too long to send emails?
Start by opening any campaign in the Noptin editor and sending a test email to yourself. If the test email fails to arrive, the issue may be related to your site’s email configuration.
2. Check Email Sending Limits
Most hosting providers and some SMTP services restrict the number of emails that can be sent within a given timeframe.
First, check if your host (or email sender) has email-sending limits. If your host is not listed on the above list, you can contact them to inquire about any hourly or daily limits.
If your host has any limits, navigate to Noptin > Settings > Emails, and adjust the Emails Per Hour field to stay within these limits.
3. Monitor for Errors
Noptin logs email delivery errors to help you identify potential issues:
- Go to Noptin > Tools > Debug Log.
- Look for recent entries showing failures or warnings.
- Address any reported errors or contact Noptin support for assistance.
4. Use a Mail Logging Plugin
WordPress may report a failure to send emails even if they were successfully dispatched, or vice versa.
- Install a plugin like WP Mail Logging.
- Send a newsletter campaign.
- Visit WP Mail Log to verify which emails were sent and whether errors occurred.
This will help distinguish between email generation issues and delivery problems.
5. Use SMTP to send your emails
By default, Noptin sends mail using the wp_mail() PHP function, which in turn sends emails through your web host. In most cases where email is not being sent, the issue is not with Noptin itself generating the email, but with the core email function on your web host.
Sending emails through WordPress’ default mail function is not always reliable. We recommend configuring an SMTP provider for consistent delivery.
What is SMTP?
SMTP stands for Simple Mail Transfer Protocol, and is the standard method for sending emails over the internet.
SMTP services are essential for email transmission and are used by email servers to send, receive, and relay outgoing mail between email senders and receivers.
Why Use SMTP?
SMTP servers provide the following advantages compared to sending your Noptin emails directly via your WordPress site:-
- SMTP servers are specifically designed to send emails, ensuring higher deliverability rates.
- They often include authentication mechanisms like SPF, DKIM, and DMARC, which verify the sender’s identity and improve email security.
- SMTP services provide better error handling and reporting, giving you insights into why certain emails may not have been delivered.
- They can handle a large volume of emails efficiently, making them suitable for websites with many newsletter subscribers and high email traffic.
Recommended SMTP Service Providers
The table below lists some of our recommended SMTP service providers and their prices.
NOTE: The prices were last updated on February 29, 2024.
| Provider | Free Plan | Starting Price | Notable Features |
|---|---|---|---|
| SendGrid | ✔️ | $19.95/month | Powerful APIs, analytics |
| Mailgun | ✔️ | $15/month | Email validation, robust logging |
| Amazon SES | ❌ | $0.10 per 1K emails | Highly scalable, cost-effective |
| SMTP.com | ❌ | $25/month | Deliverability tools, long-standing service |
| Postmark | ✔️ | $15/month | Focused on transactional emails |
| Mailjet | ✔️ | $17/month | Intuitive email builder, A/B testing |
| Brevo | ✔️ | $9/month | CRM features, transactional support |
Building your own SMTP service
If you send thousands of emails per month, it might be cheaper to build your own SMTP service instead of using a third-party server.
This also gives you more customization options and enhances data privacy, security, and reliability.
For this, we recommend you use Mail-in-a-Box. You can easily set it up on a DigitalOcean droplet and start using it right away.
6. Upload Contacts to Third-Party Email Services
If you’re using an external SMTP provider, verify if they require all recipients to be confirmed/verified within their platform.
If they do, export your Noptin subscribers and then import them into your SMTP provider’s contact list.
7. Avoid Spam Filters
Even correctly sent emails can end up in spam folders. To improve deliverability:
- Use a domain-specific sender address (e.g.,
[email protected]) - Avoid public email addresses like
@gmail.comin the From field. - Add SPF, DKIM, and DMARC records to your DNS settings.
You can test your configuration using Mail Tester or similar tools.
8. Prevent Plugin or Theme Conflicts
Sometimes, another plugin or theme can interfere with email sending:
- Temporarily deactivate all plugins except Noptin.
- Switch to a default theme (e.g., Twenty Twenty-Four).
- Retry sending an email.
If the problem resolves, reactivate your plugins one at a time to find the conflict.
Still Need Help?
If you’ve followed all the steps above and emails are still not sending or being delivered:
- Reach out to Noptin support with relevant logs and configuration details.
- Include error messages and screenshots, if possible.
We’re happy to assist you in diagnosing and resolving persistent email issues.
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