ellite/Wallos · critical · Exception

$this->ErrorInfo

Error message

$this->ErrorInfo

What it means

Thrown in smtpSend() when the SMTP server rejects the MAIL FROM envelope sender ($this->Sender, falling back to $this->From). PHPMailer first records a detailed error via setError() (localized 'from_failed' plus the address and the SMTP error), then rethrows it as $this->ErrorInfo as a critical exception. The recipient-side SMTP error text is embedded in ErrorInfo.

Solutions

  1. Check $mailer->ErrorInfo for the exact SMTP reply and fix the From address accordingly.
  2. Set From to an address the authenticated SMTP user is allowed to send as (the account itself or a verified alias/sendas).
  3. Ensure From is a valid RFC address and set Sender/envelope-from explicitly if different: $mailer->Sender = 'bounce@example.com'.
  4. Configure SPF/DKIM/DMARC for the sending domain if the server enforces alignment.
  5. Inspect the server with SMTPDebug = DEBUG_SERVER to see the raw rejection code.

Example fix

// before
$mailer->isSMTP();
$mailer->Username = 'noreply@example.com';
$mailer->From = 'someone@gmail.com'; // not allowed for this account
// after
$mailer->isSMTP();
$mailer->Username = 'noreply@example.com';
$mailer->From = 'noreply@example.com';
$mailer->Sender = 'noreply@example.com';
Defensive patterns

Strategy: validation

Validate before calling

if (!filter_var($mailer->From, FILTER_VALIDATE_EMAIL)) {
    throw new InvalidArgumentException("Invalid From address: {$mailer->From}");
}
$allowed = ['noreply@example.com', 'support@example.com'];
if (!in_array($mailer->From, $allowed, true)) {
    throw new InvalidArgumentException('From not authorized for this SMTP account');
}

Try / catch

try {
    $mailer->send();
} catch (PHPMailer\PHPMailer\Exception $e) {
    if (str_contains($mailer->ErrorInfo, 'from_failed')) {
        error_log('MAIL FROM rejected: ' . $mailer->ErrorInfo); // includes server reply
    }
}

Prevention

When it happens

Trigger: Calling send() over SMTP when $this->smtp->mail($smtp_from) returns false: the server rejects the sender address (550/553/501 replies), the address is not authorized for the authenticated user (Gmail/Office365 SPF/alias rules), or the address is syntactically invalid.

Common situations: Gmail SMTP rejecting a From address that doesn't match the authenticated account or an approved alias/sendas, sending as a domain without SPF/DKIM alignment, empty or malformed From, or Exchange servers rejecting relay attempts from unknown senders.

Related errors

AI-assisted analysis of ellite/Wallos@52820e87ca (2026-09-13). Data as JSON: /api/errors/32c70b4863facbd1. Report an issue: GitHub.

Appendix: source

Thrown at libs/PHPMailer/PHPMailer.php:2034

     *
     * @return bool
     */
    protected function smtpSend($header, $body)
    {
        $header = static::stripTrailingWSP($header) . static::$LE . static::$LE;
        $bad_rcpt = [];
        if (!$this->smtpConnect($this->SMTPOptions)) {
            throw new Exception($this->lang('smtp_connect_failed'), self::STOP_CRITICAL);
        }
        //Sender already validated in preSend()
        if ('' === $this->Sender) {
            $smtp_from = $this->From;
        } else {
            $smtp_from = $this->Sender;
        }
        if (!$this->smtp->mail($smtp_from)) {
            $this->setError($this->lang('from_failed') . $smtp_from . ' : ' . implode(',', $this->smtp->getError()));
            throw new Exception($this->ErrorInfo, self::STOP_CRITICAL);
        }

        $callbacks = [];
        //Attempt to send to all recipients
        foreach ([$this->to, $this->cc, $this->bcc] as $togroup) {
            foreach ($togroup as $to) {
                if (!$this->smtp->recipient($to[0], $this->dsn)) {
                    $error = $this->smtp->getError();
                    $bad_rcpt[] = ['to' => $to[0], 'error' => $error['detail']];
                    $isSent = false;
                } else {
                    $isSent = true;
                }

                $callbacks[] = ['issent' => $isSent, 'to' => $to[0], 'name' => $to[1]];
            }
        }

View on GitHub (pinned to 52820e87ca)