Omeka S encountered an error

Exception
The current theme is not active. Its current state is "not_found".

Details:

Exception: The current theme is not active. Its current state is "not_found". in /var/www/html/application/src/Mvc/MvcListeners.php:330
Stack trace:
#0 /var/www/html/vendor/laminas/laminas-eventmanager/src/EventManager.php(319): Omeka\Mvc\MvcListeners->preparePublicSite()
#1 /var/www/html/vendor/laminas/laminas-eventmanager/src/EventManager.php(179): Laminas\EventManager\EventManager->triggerListeners()
#2 /var/www/html/vendor/laminas/laminas-mvc/src/Application.php(304): Laminas\EventManager\EventManager->triggerEventUntil()
#3 /var/www/html/index.php(21): Laminas\Mvc\Application->run()
#4 {main}