No connection to My Book Live Duo via WD 2go App on iPhone or iPad

I am getting always following error message when I try to access my MBLD via WD 2go

Device offline
The device is not accessible. Local documents are available

I have installed latest versions of firmware and App versions:
My Book Live Duo-Firmware is from 11. April 2013 21:47:41 CEST
WD 2go App-Version 2.30

I am experiencing this problem on my iPhone 4S and iPad3. I have the problem when I am connected at home via WLAN (same WLAN like the MBLD is connected). Also when accessing via mobile network (3G) I am getting the same error message. If I use at same time my Windows Vista notebook I can access all data when using Windows Explorer. But with the WD 2go App I can access without any problems my Dropbox.

Who can help me?

I have not defined any user or any shares. I am using only the standard which is the share PUBLIC and the user ADMIN. I have not changed my folder structure on the MBLD since several weeks. My MBLD is now 6 month old. The indexing is also fully completed.

Have you been able to connect using your mobile devices in the past?

Try turning off remote access and then back on.

Yes, I have been able in the past connect. But since several weeks I am unable to access.

I have tried to turn-off remote access and switched on again. But I still have this problem.

You should contact support for further assistance with this issue.

http://support.wdc.com/contact/index.asp?wdc_lang=en