PHP error guide

Cron PHP mail or PATH command fails: meaning and fix

warning server Affects: PHP 7.4–8.4 Last verified:

Error summary

Use absolute command paths or a configured mail transport, check exit status, and do not rely on cron’s restricted PATH.

What it means

Use absolute command paths or a configured mail transport, check exit status, and do not rely on cron’s restricted PATH.

What the error means

A PHP mail transport or child process attempts to execute an external command that cron cannot resolve or that is not installed.

Why PHP produces it

The scheduled environment has a smaller PATH, while mail(), exec(), or a library delegates to a local binary.

PHP version notes

The behavior described for Cron PHP mail or PATH command fails applies to PHP 7.4–8.4 unless a narrower version is stated; exact wording can vary by SAPI and patch release.

Most common causes

  • sendmail_path names a missing binary.
  • exec calls a command by basename.
  • The MTA is unavailable in a container or minimal host.

Minimal examples

BAD — reproduces the problem

php 
@mail($to, $subject, $body);

FIXED — safer pattern

php 
if (!mail($to, $subject, $body)) { throw new RuntimeException("Mail failed"); }

Step-by-step diagnosis

  1. Inspect ini_get("sendmail_path") with the cron PHP binary.
  2. Resolve every delegated command as the cron user.
  3. Check the function result, process exit code, and protected mail logs.

Fixes

Use a configured transport or absolute command

Configure a real mail transport and fail visibly when delivery cannot be queued.

php 
$sent = mail($to, $subject, $body);
if (!$sent) {
    throw new RuntimeException("Mail transport rejected the message");
}

Common mistakes when fixing it

  • Treating mail() true as proof of final delivery.
  • Adding insecure directories to PATH.
  • Suppressing child-process stderr.

How to prevent it

  • Health-check the configured transport.
  • Use absolute executable paths.
  • Monitor queue and task failures separately.

Web server / environment notes

cron, cli, linux. External transport availability can differ from web requests.

Tags: cron,cli,linux

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