Check Email Logs First
Before adjusting any configuration, review the email logs to identify the exact error WP Postman recorded.1
Open WP Postman Email Logs
In your WordPress admin, navigate to WP Postman → Email Logs. For a full walkthrough of the logs interface, see the Email Logs documentation.
2
Locate failed delivery entries
Filter the log by Status: Failed. Click on any failed entry to expand the full SMTP response. The response code and message will tell you precisely where the delivery broke down — for example, an authentication rejection versus a connection refusal.
3
Note the error message
Copy the exact error text before proceeding. Use it to match against the common issues listed below so you apply the right fix without guesswork.
Common Issues
Emails not sending at all
Emails not sending at all
If no emails are being sent and there are no entries in the log, WP Postman is likely not yet configured with SMTP credentials. Out of the box, WP Postman needs a valid SMTP host, port, username, and password before it can deliver mail.Follow the SMTP Configuration guide to complete the setup. Once credentials are saved, use the test email feature (described below) to confirm delivery works.
Authentication error
Authentication error
An authentication error means the SMTP server accepted the connection but rejected your login credentials. Double-check that the SMTP username and password in WP Postman → SMTP Settings exactly match those provided by your email service.If you are using Gmail, standard account passwords no longer work with third-party SMTP clients. You must generate an App Password:
- Enable 2-Step Verification on your Google account at myaccount.google.com/security.
- Under Security → App Passwords, generate a new password for “Mail.”
- Paste the generated 16-character password into the WP Postman password field — do not use your regular Gmail password.
Connection timeout
Connection timeout
A connection timeout means WP Postman couldn’t establish a connection to the SMTP server at all. The most common causes are an incorrect SMTP hostname or port number.Verify both values with your email provider’s documentation. Common port configurations are:
- Port 587 with STARTTLS encryption (recommended by most providers)
- Port 465 with SSL/TLS encryption
- Port 25 (often blocked by hosting environments — avoid this port)
Emails going to spam
Emails going to spam
Spam placement usually means one of two things: your From Email address doesn’t match the domain you’re sending from, or your domain is missing SPF and DKIM authentication records.
- Set the From Email in WP Postman to an address on the same domain as your site (e.g.,
hello@yourdomain.com, not a personal Gmail address). - Add SPF and DKIM records to your DNS — see the Setting Up SPF and DKIM section below.
"Could not connect to SMTP" error
"Could not connect to SMTP" error
This error often indicates a firewall block rather than a configuration problem. Many hosting environments, including some ISPs, block outbound traffic on port 25 to prevent spam. If you’re using port 25, switch to port 587 (STARTTLS) or port 465 (SSL).If the error persists on port 587 or 465, contact WP Stratos support to confirm there are no outbound SMTP restrictions on your specific plan.
Recipient address rejected
Recipient address rejected
A recipient rejection means the receiving server refused to accept the message. This can happen if the recipient’s mail server has blocklisted your sending IP or domain. To work around this:
- Try changing the From Email to a different address or domain.
- Switch to a reputable transactional email provider (SendGrid, Mailgun, or Amazon SES), whose IP addresses are monitored and maintained to stay off blocklists.
- Ask the recipient to check if their IT team has blocked your domain, particularly for corporate or enterprise email systems.
Setting Up SPF and DKIM
SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) are DNS-based authentication standards that prove to receiving mail servers that emails from your domain are legitimate. SPF specifies which servers are allowed to send mail on behalf of your domain. DKIM adds a cryptographic signature to each outgoing message that recipients can verify against a public key in your DNS. Together, these two records significantly reduce the chance of your emails being flagged as spam or rejected outright. They are especially important when using a third-party SMTP provider.SPF and DKIM record values are provided by your SMTP provider (e.g., SendGrid, Mailgun, Postmark). Log in to your provider’s dashboard to find the exact TXT record values, then add them to your domain’s DNS as TXT records. For instructions on adding DNS records, see the DNS Configuration guide.
Send a Test Email
After making any configuration change, always send a test email to confirm delivery is working before relying on it in production.1
Open SMTP Settings
Go to WP Postman → SMTP Settings in your WordPress admin.
2
Send a test email
Scroll to the Send Test Email section, enter a recipient address you have access to, and click Send Test Email.
3
Check the result
If the test succeeds, check the recipient inbox (and spam folder). If it fails, a new entry will appear in Email Logs with the SMTP error — use that to guide your next troubleshooting step.