Thanks I got it working
What info do you need?
Here is the full error message I'm getting:
TypeError : htmlspecialchars(): Argument #1 ($string) must be of type string, array given dans htmlspecialchars() (/home/tbpzego/www/core/lib/Drupal/Component/Utility/Html.php ligne 432)
#0 /home/tbpzego/www/core/lib/Drupal/Component/Utility/Html.php(432): htmlspecialchars(Array, 11, 'UTF-8')
#1 /home/tbpzego/www/core/lib/Drupal/Component/Render/FormattableMarkup.php(270): Drupal\Component\Utility\Html::escape(Array)
#2 /home/tbpzego/www/core/lib/Drupal/Component/Render/FormattableMarkup.php(216): Drupal\Component\Render\FormattableMarkup::placeholderEscape(Array)
#3 /home/tbpzego/www/core/lib/Drupal/Core/StringTranslation/TranslatableMarkup.php(195): Drupal\Component\Render\FormattableMarkup::placeholderFormat('@requirements_m...', Array)
#4 /home/tbpzego/www/core/lib/Drupal/Component/Utility/ToStringTrait.php(15): Drupal\Core\StringTranslation\TranslatableMarkup->render()
#5 /home/tbpzego/www/core/lib/Drupal/Core/Messenger/Messenger.php(54): Drupal\Core\StringTranslation\TranslatableMarkup->__toString()
#6 /home/tbpzego/www/core/lib/Drupal/Core/Messenger/Messenger.php(46): Drupal\Core\Messenger\Messenger->addMessage(Object(Drupal\Core\StringTranslation\TranslatableMarkup), 'error', false)
#7 /home/tbpzego/www/core/includes/install.inc(1052): Drupal\Core\Messenger\Messenger->addError(Object(Drupal\Core\StringTranslation\TranslatableMarkup))
#8 /home/tbpzego/www/core/modules/system/src/Form/ModulesListForm.php(463): drupal_check_module('symfony_mailer')
#9 /home/tbpzego/www/core/modules/system/src/Form/ModulesListForm.php(481): Drupal\system\Form\ModulesListForm->buildModuleList(Object(Drupal\Core\Form\FormState))
#10 [internal function]: Drupal\system\Form\ModulesListForm->submitForm(Array, Object(Drupal\Core\Form\FormState))
#11 /home/tbpzego/www/core/lib/Drupal/Core/Form/FormSubmitter.php(114): call_user_func_array(Array, Array)
#12 /home/tbpzego/www/core/lib/Drupal/Core/Form/FormSubmitter.php(52): Drupal\Core\Form\FormSubmitter->executeSubmitHandlers(Array, Object(Drupal\Core\Form\FormState))
#13 /home/tbpzego/www/core/lib/Drupal/Core/Form/FormBuilder.php(597): Drupal\Core\Form\FormSubmitter->doSubmitForm(Array, Object(Drupal\Core\Form\FormState))
#14 /home/tbpzego/www/core/lib/Drupal/Core/Form/FormBuilder.php(325): Drupal\Core\Form\FormBuilder->processForm('system_modules', Array, Object(Drupal\Core\Form\FormState))
#15 /home/tbpzego/www/core/lib/Drupal/Core/Controller/FormController.php(73): Drupal\Core\Form\FormBuilder->buildForm(Object(Drupal\system\Form\ModulesListForm), Object(Drupal\Core\Form\FormState))
#16 [internal function]: Drupal\Core\Controller\FormController->getContentResult(Object(Symfony\Component\HttpFoundation\Request), Object(Drupal\Core\Routing\RouteMatch))
#17 /home/tbpzego/www/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array(Array, Array)
#18 /home/tbpzego/www/core/lib/Drupal/Core/Render/Renderer.php(580): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
#19 /home/tbpzego/www/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(124): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure))
#20 /home/tbpzego/www/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array)
#21 /home/tbpzego/www/vendor/symfony/http-kernel/HttpKernel.php(169): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
#22 /home/tbpzego/www/vendor/symfony/http-kernel/HttpKernel.php(81): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1)
#23 /home/tbpzego/www/core/lib/Drupal/Core/StackMiddleware/Session.php(58): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#24 /home/tbpzego/www/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(48): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#25 /home/tbpzego/www/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#26 /home/tbpzego/www/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#27 /home/tbpzego/www/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(48): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#28 /home/tbpzego/www/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(51): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#29 /home/tbpzego/www/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#30 /home/tbpzego/www/core/lib/Drupal/Core/DrupalKernel.php(718): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#31 /home/tbpzego/www/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request))
#32 {main}