使用PHPMailer发送邮件报错：调用未定义方法isSTMP()求助

Hey, let's break down what's going on here and get your email sending working smoothly.

The Root Cause #

That fatal error Fatal error: Uncaught Error: Call to undefined method PHPMailer\PHPMailer\PHPMailer::isSTMP() is a simple typo. The correct method name in PHPMailer for enabling SMTP is isSMTP()—you accidentally wrote isSTMP() (swapped the M and T in SMTP) somewhere in your code, which the error log confirms.

Your Test Code #

<!DOCTYPE html> 
<html> 
<head> 
<title></title> 
</head> 
<body> 
<?php 
require "vendor/autoload.php"; 
use PHPMailer\PHPMailer\PHPMailer; 
use PHPMailer\PHPMailer\Exception; 

$developmentMode = true; 
$mailer = new PHPMailer($developmentMode); 

try { 
    $mailer->SMTPDebug = 2; 
    $mailer->isSMTP(); //edited here 
    if ($developmentMode) { 
        $mailer->SMTPOptions = [ 
            'ssl'=> [ 
                'verify_peer' => false, 
                'verify_peer_name' => false, 
                'allow_self_signed' => true 
            ] 
        ]; 
    } 
    $mailer->Host = 'smtp.gmail.com'; 
    $mailer->SMTPAuth = true; 
    $mailer->Username = "mygmail@gmail.com"; 
    $mailer->Password = "password"; 
    $mailer->SMTPSecure = 'tls'; 
    $mailer->Port = 587; 

    $mailer-> setFrom("mygmail@gmail.com", "Izaya"); 
    $mailer->addAddress("anothergmail@gmail.com","orihara"); 

    $mailer->isHTML(true); 
    $mailer->Subject = "Hey There"; 
    $mailer->Body = "NICE TO MEET YOU IZAYA "; 

    $mailer->send(); 
    $mailer->ClearAllRecipients(); 
    echo "Mail has been Sent"; 
}catch (Exception $e) { 
    echo "Email Error.INFO:" . $mailer->ErrorInfo; 
} 
?> 
</body> 
</html>

Fixes & Next Steps #

I see you already edited the line to isSMTP() (marked with //edited here)—that's exactly the fix for the typo error. But if you still run into issues, check these common pitfalls:

• Composer Installation: Make sure you installed PHPMailer correctly via Composer, and the vendor/autoload.php path is accurate.
• Gmail SMTP Quirks:
  • Gmail no longer allows regular account passwords for SMTP access unless you enable 2-step verification and generate an App Password (use this instead of your regular password).
  • Your current settings for Host = 'smtp.gmail.com', SMTPSecure = 'tls', and Port = 587 are correct—don't change those.
• Method Call Spacing: You have an extra space in $mailer-> setFrom(...)—remove the space between -> and setFrom to make it $mailer->setFrom(...); this could cause unexpected issues.

Pro Tip #

Leaving SMTPDebug = 2 enabled in development is smart—it will print detailed SMTP connection logs, which is super helpful for troubleshooting any future authentication or delivery problems.

内容的提问来源于stack exchange，提问作者Izaya