Fix Email Not Sending

Check Email Logs First

# Mail log location
sudo tail -f /var/log/mail.log      # Debian/Ubuntu
sudo tail -f /var/log/maillog       # CentOS/RHEL
sudo journalctl -u postfix -f       # Postfix with systemd

Common Causes

1. SMTP Port Blocked

Many ISPs block port 25 (outbound SMTP):

# Test connection
telnet gmail-smtp-in.l.google.com 25
# If fails, use port 587 (submission) with authentication

2. No Reverse DNS (PTR Record)

Many email servers reject mail without PTR:

# Check PTR
dig -x YOUR_SERVER_IP

Contact Hostxpeed to set PTR record for your IP.

3. SPF/DKIM/DMARC Missing

Add DNS records:

# SPF example
v=spf1 ip4:YOUR_SERVER_IP include:spf.your-email-provider.com ~all

# Verify SPF
dig TXT yourdomain.com

4. IP Blacklisted

# Check blacklists
https://mxtoolbox.com/blacklists.aspx

5. Mail Service Not Running

# Postfix
sudo systemctl status postfix

# Sendmail
sudo systemctl status sendmail

# Exim
sudo systemctl status exim4

Test Email Sending

# Using mail command
echo "Test email body" | mail -s "Test Subject" recipient@example.com

# Using sendmail
sendmail recipient@example.com <

# Check sendmail_path in php.ini
sendmail_path = /usr/sbin/sendmail -t -i