• Troubleshooting PHPMailer Problems
• Loading classes
• Using composer
• Using PHPMailer's own autoloader
• Enabling debug output
• "SMTP Error: Could not connect to SMTP host."
• GoDaddy
• Read the SMTP transcript
• DNS failures
• Check it's there at all
• Check it's a mail server
• Firewall redirection
• SELinux blocking
• IPv6 blocking
• Authentication failures
• Gmail, OAuth2 and "Allow less secure apps"
• Exchange Online, Outlook.com, live.com, office365.com, hotmail.com and other Microsoft domains
• Using encryption
• Check you have the openssl extension
• Encryption flavours
• Opportunistic TLS
• Certificate verification failure
• Checking CA certificates
• Updating CA certificates
• cURL error 60
• Testing SSL outside PHP
• "Could not instantiate mail function"
• Addressing
• Messages end up in the spam folder
• It's still not working!
• Where else to get help?