500 Internal Server Error after changing language

Hi,
I got "500 Internal Server Error" after changing language. How can no lognger reach the dashboard or settings. How can I reverse the change, and move back to the previous language ?

Hello, Are you using a self-hosted installation?

If so, enable APP_DEBUG = true in your .ENV file.

Be carefull and do it on a local environment to not expose sensitive data on Internet.

Thanks,
The installation is self hosted. I have now enabled APP_DEBUG = true in my .env file
I get this message in the log:
LOG.error: Call to a member function route() on null {"userId":1,"exception":{}}
Then, I have a page full of exception errors like this:
in /var/www/html/akaunting/modules/Receipt/Listeners/AdminMenu.php (line 22)
{
$user = auth()->user();
if ($user->can('read-receipt-receipts')) {
$item = $event->menu->whereTitle(trans_choice('general.purchases', 2));
$item->route('receipt.index', trans_choice('receipt::general.menu', 2), [], 10, ['icon' => '']);
}
}
}