Expected behaviour

I want to browse my SFTP External Storage on owncloud server

Actual behaviour

Android app says 'Nothing here, send something'
But all other ownCloud client (Linux Desktop and WebUI) work fine

Steps to reproduce

1. Configure ldap_backend on owncloud server
2. Configure an external remote share with SFTP protocol
3. Browse to the external share folder with Android App

Can this problem be reproduced with the official owncloud server?
no because it need an external mount storage with SFTP and LDAP user backend

Environment data

Android version:
6.0.1

Device model: Samsung Galaxy S6 SM G920F

Stock or customized system: Stock

ownCloud app version: 2.0.0

ownCloud server version: ownCloud 9.0.2 (stable)

Logs

Web server error log

nginx_owncloud: 192.168.57.81 - pgindraud [15/May/2016:11:27:17 +0200] "GET /ocs/v1.php/cloud/capabilities?format=json HTTP/1.1" 200 607 "-" "Mozilla/5.0 (Android) ownCloud-android/2.0.0"
nginx_owncloud: 192.168.57.81 - pgindraud [15/May/2016:11:27:17 +0200] "PROPFIND /remote.php/webdav/LINUX_HOME/ HTTP/1.1" 503 234 "-" "Mozilla/5.0 (Android) ownCloud-android/2.0.0"

ownCloud log (data/owncloud.log)

ownCloud[9730]: {webdav} Exception: {
"Message":"HTTP/1.1 503 Storage not available",
"Exception":"Sabre\DAV\Exception\ServiceUnavailable",
"Code":0,
"Trace":"
#0 /var/www/owncloud/3rdparty/sabre/dav/lib/DAV/Server.php(903): OCA\DAV\Connector\Sabre\ObjectTree->getNodeForPath('LINUX_HOME')
#1 /var/www/owncloud/3rdparty/sabre/dav/lib/DAV/CorePlugin.php(334): Sabre\DAV\Server->getPropertiesForPath('LINUX_HOME', Array, 0)
#2 [internal function]: Sabre\DAV\CorePlugin->httpPropFind(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))
#3 /var/www/owncloud/3rdparty/sabre/event/lib/EventEmitterTrait.php(105): call_user_func_array(Array, Array)
#4 /var/www/owncloud/3rdparty/sabre/dav/lib/DAV/Server.php(459): Sabre\Event\EventEmitter->emit('method:PROPFIND', Array)
#5 /var/www/owncloud/3rdparty/sabre/dav/lib/DAV/Server.php(248): Sabre\DAV\Server->invokeMethod(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))
#6 /var/www/owncloud/apps/dav/appinfo/v1/webdav.php(55): Sabre\DAV\Server->exec()
#7 /var/www/owncloud/remote.php(138): require_once('/var/www/ownclo...')
#8 {main}","File":"/var/www/owncloud/apps/dav/lib/connector/sabre/objecttree.php","Line":159,"User":"ae877d96-3ba9-1035-95bb-6fbf9d048cee"}