Could not load message.

Steps to reproduce

Expected behaviour

Tell us what should happen

Actual behaviour

Tell us what happens instead

Error

OCA\Mail\Exception\ServiceException: Could not load message
  at OCA\Mail\Service\MailManager::getImapMessage
     /var/www/nextcloud/apps/mail/lib/Controller/MessagesController.php, line 223
  at OCA\Mail\Controller\MessagesController::getBody
     /var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php, line 204
  at OC\AppFramework\Http\Dispatcher::executeController
     /var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php, line 118
  at OC\AppFramework\Http\Dispatcher::dispatch
     /var/www/nextcloud/lib/private/AppFramework/App.php, line 153
  at OC\AppFramework\App::main
     /var/www/nextcloud/lib/private/Route/Router.php, line 321
  at OC\Route\Router::match
     /var/www/nextcloud/lib/base.php, line 1061
  at OC::handleRequest
     /var/www/nextcloud/index.php, line 25