[BUG] if a visitor forgets to activate the GDPR checkbox

[morange]

TYPO3 config

• PHP Version 8.2.7
• Apache
• TYPO3 v12.4.24
• EXT:powermail
• 3-step form witch GDPR checkbox and powermail captcha

Error message

Wed, 08 Jan 2025 15:33:52 +0100 [CRITICAL] request="e21849d02c6dd" component="TYPO3.CMS.Core.Error.ProductionExceptionHandler": Core: Exception handler (WEB: FE): TYPO3\CMS\Extbase\Security\Exception\InvalidArgumentForHashGenerationException, code #1255072832, file /var/www/vhosts/xxxx.alfahosting-server.de/PROJECT/vendor/typo3/cms-extbase/Classes/Mvc/Controller/MvcPropertyMappingConfigurationService.php, line 96: The form field "tx_powermail_pi1[field][datenschutzhinweis][][]" is invalid. Reason: "[]" used not as last argument, but somewhere in the middle (like foo[][bar]). - {"mode":"WEB","application_mode":"FE","exception_class":"TYPO3\\CMS\\Extbase\\Security\\Exception\\InvalidArgumentForHashGenerationException","exception_code":1255072832,"file":"/var/www/vhosts/rtavuk3g.web146.alfahosting-server.de/typo3.dvl-sachsen.de/vendor/typo3/cms-extbase/Classes/Mvc/Controller/MvcPropertyMappingConfigurationService.php","line":96,"message":"The form field \"tx_powermail_pi1[field][datenschutzhinweis][][]\" is invalid. Reason: \"[]\" used not as last argument, but somewhere in the middle (like foo[][bar]).","request_url":"https://project.tld/formular.html?tx_powermail_pi1%5Baction%5D=checkConfirmation&tx_powermail_pi1%5Bcontroller%5D=Form&cHash=34a7fc36db79e96555d57191e5485011","exception":null}

What causes the error message?

The users fill out the 3-step form correctly, but overlook the checkbox for the GDPR regulations at the end TAB.
Visitors receive an error message after submitting (PHP validated form), activate the GDPR checkbox and enter the correct number for the captcha.