SMBclient not installed - Nextcloud Snap

Moin Moin,

ich habe ein Problem mit meiner Nextcloud: Bei dem externem Speicher meint Nextcloud, dass smbclient nicht installiert ist. Dieser ist aber installiert. Muss ich Nextcloud noch berechtigungen geben, damit die auf den smbclient zugreifen kann? Ich verwende Nextcloud 16/stable und habe alle Pakete aktuell.
Der SMB-TEST (App) gibt folgende Fehler aus:

Using backend: ...

Error while loading share content.

Icewind\SMB\Exception\DependencyException: No valid backend available, ensure smbclient is in the path or php-smbclient is installed

    /var/snap/nextcloud/16402/nextcloud/extra-apps/smb_test/lib/ShareFactory.php - line 29:

    Icewind\SMB\ServerFactory->createServer(null, Icewind\SMB\BasicAuth {})

    /var/snap/nextcloud/16402/nextcloud/extra-apps/smb_test/lib/Controller/SmbController.php - line 94:

    OCA\SMBTest\ShareFactory->getShare(null, null, null, null, null)

    /snap/nextcloud/16402/htdocs/lib/private/AppFramework/Http/Dispatcher.php - line 166:

    OCA\SMBTest\Controller\SmbController->dir(null, null, null, null, null, null)

    /snap/nextcloud/16402/htdocs/lib/private/AppFramework/Http/Dispatcher.php - line 99:

    OC\AppFramework\Http\Dispatcher->executeController(OCA\SMBTest\ ... {}, "dir")  

    /snap/nextcloud/16402/htdocs/lib/private/AppFramework/App.php - line 126:

    OC\AppFramework\Http\Dispatcher->dispatch(OCA\SMBTest\ ... {}, "dir")  

    /snap/nextcloud/16402/htdocs/lib/private/AppFramework/Routing/RouteActionHandler.php - line 47:

    OC\AppFramework\App::main("OCA\\SMBTes ... r", "dir", OC\AppFramew ... {}, { _route: "smb_test.smb.dir"})  

    OC\AppFramework\Routing\RouteActionHandler->__invoke({ _route: "smb_test.smb.dir"})  

    /snap/nextcloud/16402/htdocs/lib/private/Route/Router.php - line 297:

    call_user_func(OC\AppFramew ... {}, { _route: "smb_test.smb.dir"})  

    /snap/nextcloud/16402/htdocs/lib/base.php - line 975:

    OC\Route\Router->match("/apps/smb_test/dir")  

    /snap/nextcloud/16402/htdocs/index.php - line 42:

    OC::handleRequest()

dpkg --list|grep 'smb\|samba'  
ii  libsmbclient:amd64                    2:4.7.6+dfsg~ubuntu-0ubuntu2.11    amd64        shared library for communication with SMB/CIFS servers
ii  php-smbclient                         0.8.0-3build2                      amd64        PHP wrapper for libsmbclient
ii  python-samba                          2:4.7.6+dfsg~ubuntu-0ubuntu2.11    amd64        Python bindings for Samba
ii  samba-common                          2:4.7.6+dfsg~ubuntu-0ubuntu2.11    all          common files used by both the Samba server and client
ii  samba-common-bin                      2:4.7.6+dfsg~ubuntu-0ubuntu2.11    amd64        Samba common files used by both the server and the client
ii  samba-libs:amd64                      2:4.7.6+dfsg~ubuntu-0ubuntu2.11    amd64        Samba core libraries
ii  smbclient                             2:4.7.6+dfsg~ubuntu-0ubuntu2.11    amd64        command-line SMB/CIFS clients for Unix