Error - Middleware Dispatcher


after the update to version 17.0.6 I get the following error message in the log:

TypeError: Argument 3 passed to OC\AppFramework\Middleware\MiddlewareDispatcher::beforeOutput() must be of the type string, null given, called in /var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php on line 123

But Nextcloud is currently running without problems. Does anyone know this issue? Can I ignore it?
What is it used for MiddlewareDispatcher?
Nextcloud is installed on a RaspberryPi 3 (NextcloudPi).

Kind regards,

Hi micson,
is there an option to enlarge the error mesage, or could you at least past the raw message, too?
I assume that this issue is caused by an app, but the message is to short to figure out which one it is. Alternativly you could try to figure out, how to reporduce the error. Open the log in a different tap and see when the error appears.
If you are able to reproduce the error, start disabling app. Then you know which one it might be.

Sorry, here the enlarged erroro message:

This ist the section in die Dispatcher.php:

// depending on the cache object the headers need to be changed
$out[0] = $this->protocol->getStatusHeader($response->getStatus(),
$response->getLastModified(), $response->getETag());
$out[1] = array_merge($response->getHeaders());
$out[2] = $response->getCookies();
$out[3] = $this->middlewareDispatcher->beforeOutput(
$controller, $methodName, $response->render() ######### this is line 123
$out[4] = $response;

It seems to be the bookmarks app, isnt’t it?
However, the error only appeared once yesterday.

I think there are two issues with Bookmarks discussing this error message:


Maybe you can find additional and or helpfull information there.

Thanks for the information. I will keep an eye on the discussions.