Troubleshooting Email Not Sending

When your emails fail to send, it disrupts your business communications. This guide provides a systematic approach to diagnosing and resolving common outgoing email problems. Work through each section in order — most issues are resolved in the first few steps.

Quick Diagnosis Checklist

Before diving into detailed troubleshooting, check these common causes:

1. Is your internet connection working? (Try loading a website)
2. Are you using the correct SMTP settings? (Server, port, username, password)
3. Has your password changed recently?
4. Is your mailbox or hosting account suspended?
5. Are you getting a specific error message? (Check below for your error)

Step 1: Verify Your SMTP Settings

Incorrect SMTP settings are the most common reason emails fail to send. Verify these settings in your email client:

Important: Port 25 is blocked on most networks and hosting providers. Always use port 465 or 587.

Verifying in Popular Email Clients

Outlook:

1. Go to File → Account Settings → Account Settings
2. Select your account → Change
3. Click More Settings → Outgoing Server tab
4. Ensure My outgoing server (SMTP) requires authentication is checked
5. Under Advanced tab, verify port and encryption

Thunderbird:

1. Go to Account Settings → Outgoing Server (SMTP)
2. Select your server → Edit
3. Verify the server, port, and security settings

Apple Mail:

1. Go to Mail → Preferences → Accounts
2. Select your account → Server Settings
3. Under Outgoing Mail Server (SMTP), verify settings

Step 2: Test Your Login Credentials

A failed authentication will prevent sending. Test your credentials:

1. Log in to webmail at https://yourdomain.com/webmail or https://mail.yourdomain.com
2. If login fails, your password may be wrong or your account may be locked
3. Reset your password through cPanel: Email → Email Accounts → Manage → Change Password

Tip: If you recently changed your password, update it in all devices and email clients. A device with the old password will cause repeated failed login attempts, which can trigger an IP block.

Step 3: Check for IP Blocks

If you entered the wrong password multiple times, your IP address may have been temporarily blocked by the server's firewall (CSF/LFD or Imunify360).

Signs of an IP block:

• Webmail loads but email client cannot connect
• Connection timeout errors
• "Cannot connect to server" messages

Solution:

1. Find your public IP at https://whatismyip.com
2. Contact {{SUPPORT_EMAIL}} and provide your IP address
3. We will check the firewall and unblock your IP if needed

Step 4: Check Your Sending Limits

{{COMPANY_NAME}} hosting plans have per-hour sending limits to prevent spam abuse:

If you hit the sending limit, emails will queue and be delivered in the next hour. The error message typically says:

• "Too many connections"
• "Rate limit exceeded"
• "Sending quota exceeded"

Solution: Wait for the next hour or contact support to adjust your limit if your business requires higher volume.

Step 5: Check for Bounced Emails

If the email appears to send but the recipient never receives it, check for bounce-back messages in your inbox. Common bounce errors:

Step 6: Check DNS Records

Missing or misconfigured DNS records can cause outgoing email to be rejected by receiving servers:

1. SPF record — Authorizes your server to send email for your domain
2. DKIM record — Adds a digital signature to verify message integrity
3. rDNS (PTR record) — Maps your server IP to a hostname (managed by your hosting provider)

Use MXToolbox to check: https://mxtoolbox.com/diagnostic.aspx

Step 7: Test with Webmail

To determine if the problem is with your email client or the server:

1. Log in to webmail at https://yourdomain.com/webmail
2. Compose and send a test email to a Gmail or Outlook address
3. If webmail works but your email client does not — the issue is with your client settings
4. If webmail also fails — the issue is server-side; contact support

Step 8: Check Server Status

Occasionally, the mail server itself may have an issue:

1. Check the {{COMPANY_NAME}} status page for any reported outages
2. If no outage is reported but the issue persists, contact support with:

- Your domain name

- The recipient email address

- The exact error message (screenshot if possible)

- The date and time of the failed attempt

Common Error Messages and Solutions

Related Articles

• Troubleshooting Email Not Receiving
• What to Do If Your Email Is Blacklisted
• Understanding SPF, DKIM, and DMARC Records

Still unable to send email? Contact our support team at {{SUPPORT_URL}} or email {{SUPPORT_EMAIL}} with your domain name, the error message, and the recipient address. We will investigate and resolve the issue promptly.