# Mautic Form Preview / Form Submission - 500 Error

**URL:** <https://forum.mautic.org/t/mautic-form-preview-form-submission-500-error/20623>\
**Category:** Product Support\
**Tags:** mautic-3\
**Created:** [August 28, 2021, 4:14am UTC](https://forum.mautic.org/t/mautic-form-preview-form-submission-500-error/20623 "2021-08-28T04:14:09Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![condoexchange](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/condoexchange/32/682_2.png) [@condoexchange](https://forum.mautic.org/u/condoexchange)\
**Post date:** [October 4, 2021, 2:09pm UTC](https://forum.mautic.org/t/mautic-form-preview-form-submission-500-error/20623/3 "2021-10-04T14:09:55Z")

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Unable to edit Forms. " Uh oh! I think I broke it. If I do it again, please report me to the system administrator! #### **500** Internal Server Error"

Please advice how to resolve.

Upon checking the log, this errors shows up:  
[2021-10-04 09:02:46] mautic.CRITICAL: Uncaught PHP Exception Symfony\Component\Form\Exception\UnexpectedTypeException: “Expected argument of type “null or string”, “boolean” given” at /home/abc/public\_html/www/mautic/vendor/symfony/form/Extension/Core/DataMapper/RadioListMapper.php line 49 {“exception”:"[object] (Symfony\Component\Form\Exception\UnexpectedTypeException(code: 0): Expected argument of type “null or string”, “boolean” given at /home/abc/public\_html/www/mautic/vendor/symfony/form/Extension/Core/DataMapper/RadioListMapper.php:49)"}

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