Error on install

This issue is due to improper declaration of function validatedBy() in Drupal\Core\Validation\Plugin\Validation\Constraint\UniqueFieldConstraint.
You may have to open an issue for Drupal core. Hope this helps. Thanks.

I have similar issues when upgrading from 4.0.0 to 4.0.1 on Drupal 10.3.

Fatal error: Declaration of Drupal\Core\Entity\Plugin\Validation\Constraint\EntityHasFieldConstraint::getDefaultOption() must be compatible with Symfony\Component\Validator\Constraint::getDefaultOption(): ?string in /app/app/web/core/lib/Drupal/Core/Entity/Plugin/Validation/Constraint/EntityHasFieldConstraint.php on line 50

PHP Fatal error: Declaration of Drupal\ckeditor5\Plugin\Validation\Constraint\ToolbarItemDependencyConstraint::getRequiredOptions() must be compatible with Symfony\Component\Validator\Constraint::getRequiredOptions(): array in /app/app/web/core/modules/ckeditor5/src/Plugin/Validation/Constraint/ToolbarItemDependencyConstraint.php on line 39

Downgrading to 4.0.0 fixes the problem.

Duplicate of 🐛 The module no longer works with Drupal 10 Active