PHP Warning and PHP Fatal error

Thank you for reply.

The specified field already has an email address entered. In that state, the above error occurs.

Looking at the code where the error occurs,
$transports = $this->getTransports();
seems to become null.

When sending emails other than the wp-cerber lockout email, the above does not become null.
Could you think of any reasons why it sometimes becomes null and sometimes does not?

Here are the test results.

Mailer: postsmtp
HostName: test-sp
cURL Version: 7.68.0
OpenSSL Version: OpenSSL/1.0.2u
OS: Darwin MBP 23.1.0 Darwin Kernel Version 23.1.0: Mon Oct 9 21:27:24 PDT 2023; root:xnu-10002.41.9~6/RELEASE_ARM64_T6000 arm64
PHP: Darwin 8.1.13 C
PHP Dependencies: iconv=Yes, spl_autoload=Yes, openssl=Yes, sockets=Yes, allow_url_fopen=Yes, mcrypt=No, zlib_encode=Yes
WordPress: 6.5.5 ja UTF-8
WordPress Theme: test-sp
WordPress Plugins: Query Monitor, Post SMTP, AddQuicktag, Advanced Custom Fields PRO, Breadcrumb NavXT, Classic Editor, Custom Post Type UI, Yoast Duplicate Post, Intuitive Custom Post Order, SVG Support, Advanced Editor Tools, WordPress Importer, WP All Export Pro, WP All Import Pro, WP Cerber Security, Anti-spam & Malware Scan, WP Multibyte Patch, WP All Import – ACF Add-On
WordPress wp_mail Owner: /wp-content/plugins/post-smtp/Postman/PostmanWpMailBinder.php
WordPress wp_mail Filter(s): wp_staticize_emoji_for_email, PostsmtpMailer->get_mail_args
Postman: 2.9.8
Postman Sender Domain (Envelope|Message): test-sp.jp | test-sp.jp
Postman Prevent Message Sender Override (Email|Name): Yes | Yes
Postman Active Transport: Default (smtp:none:none://localhost:25)
Postman Active Transport Status (Ready|Connected): No | No
Postman Deliveries (Success|Fail): 104 | 0

@aqibkhan9

Thank you for confirming.
Could you specifically explain me how you conducted the tests?

Did you simply click “Click to send test” in the Lockout notification? Or did you actually perform suspicious activities multiple times to trigger the lockout notification?

The error actually occurs not with the test send, but with the lockout notification that is triggered in real situations.

@aqibkhan9

Thank you for your reply.

The lockout can be triggered by setting the wp-cerber lockout fields as follows:

• Limit on the allowed number of alerts = 0
• Lockout notification (send notification if the number of active lockouts above) = 0

Then,
try repeatedly requesting https://example.com/info.php (a non-existent PHP file).
This should trigger the lockout.
Could you please confirm this?