SMB external storage broken in NC 13

Log error:
Fatal webdav Sabre\DAV\Exception\ServiceUnavailable: Storage with mount id 24 is not available
/home/nextcloud/public_html/3rdparty/sabre/dav/lib/DAV/Tree.php - line 76: OCA\DAV\Connector\Sabre\Directory->getChild(‘ResFiles’)
/home/nextcloud/public_html/3rdparty/sabre/dav/lib/DAV/Server.php - line 967: Sabre\DAV\Tree->getNodeForPath(‘files/rtn361/Re…’)
/home/nextcloud/public_html/3rdparty/sabre/dav/lib/DAV/Server.php - line 1666: Sabre\DAV\Server->getPropertiesIteratorForPath(‘files/rtn361/Re…’, Array, 1)
/home/nextcloud/public_html/3rdparty/sabre/dav/lib/DAV/CorePlugin.php - line 355: Sabre\DAV\Server->generateMultiStatus(Object(Generator), false)
[internal function] Sabre\DAV\CorePlugin->httpPropFind(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))
/home/nextcloud/public_html/3rdparty/sabre/event/lib/EventEmitterTrait.php - line 105: call_user_func_array(Array, Array)
/home/nextcloud/public_html/3rdparty/sabre/dav/lib/DAV/Server.php - line 479: Sabre\Event\EventEmitter->emit(‘method PROPFIND’, Array)
/home/nextcloud/public_html/3rdparty/sabre/dav/lib/DAV/Server.php - line 254: Sabre\DAV\Server->invokeMethod(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))
/home/nextcloud/public_html/apps/dav/lib/Server.php - line 283: Sabre\DAV\Server->exec()
/home/nextcloud/public_html/apps/dav/appinfo/v2/remote.php - line 35: OCA\DAV\Server->exec()
/home/nextcloud/public_html/remote.php - line 164: require_once(’/home/nextcloud…’)


I'm also seeing these:
Fatal	webdav	Icewind\SMB\Exception\Exception: Unknown error (104) for /ncncloud
/home/nextcloud/public_html/apps/files_external/3rdparty/icewind/smb/src/Exception/Exception.php - line 35: Icewind\SMB\Exception\Exception unknown('/nix_owncloud', 104)
/home/nextcloud/public_html/apps/files_external/3rdparty/icewind/smb/src/NativeState.php - line 49: Icewind\SMB\Exception\Exception fromMap(Array, 104, '/nccloud')

Nextcloud 13_:
Operating system and version: Centos 7 
Apache 2.4
PHP version 7.1

Since upgrading to NC 13 final, which I did through the web UI, Samba storage has been intermittently disconnecting.

I did try adding client max protocol SMB3 to /etc/samba/smb.conf, which didn't help.

    [global]
        client max protocol = SMB3