phpmailerHow do I enable debug mode in PHPMailer?

Debug mode in PHPMailer can be enabled by setting the SMTPDebug property. This property is available on the PHPMailer class and can be set to any of the following values:

• 0: No debug output
• 1: Commands
• 2: Data and commands
• 3: As 2 plus connection status
• 4: Low-level data output

Example code

// Enable SMTP debugging
// 0 = off (for production use)
// 1 = client messages
// 2 = client and server messages
$mail->SMTPDebug = 2;

Output example

SERVER -> CLIENT: 220 smtp.example.com ESMTP Postfix
CLIENT -> SERVER: EHLO localhost
SERVER -> CLIENT: 250-smtp.example.com
SERVER -> CLIENT: 250-PIPELINING
SERVER -> CLIENT: 250-SIZE 10240000
SERVER -> CLIENT: 250-VRFY
SERVER -> CLIENT: 250-ETRN
SERVER -> CLIENT: 250-STARTTLS
SERVER -> CLIENT: 250-ENHANCEDSTATUSCODES
SERVER -> CLIENT: 250-8BITMIME
SERVER -> CLIENT: 250 DSN

Helpful links

• PHPMailer Documentation
• SMTP Debugging in PHPMailer

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