Error 906 in Android App

Using the 6 TB My Cloud. Bit I have issues with the Android App on my LG G5. The App works well if I am connected to the same WIFI network as the WD My Cloud. But if I want to use a mobile connection I get only Error 906 (networkconnection) I allready tried to reinstall the app. and updated the firmware of the mycloud. But it did not solve the problem.
Is there a solution for this? (Another solution than never buy WD products again?)

Regards

Have you enabled Remote Access via the My Cloud Dashboard > Settings > General > Cloud Access?
Does the Cloud Access Connection Status indicate “Connected” after enabling Remote Access?
Have you setup a User for Remote Access via the My Cloud Dashboard and created a MyCloud.com account?
Can you access the MyCloud.com user web portal using a web browser and view your My Cloud?

See the My Cloud Dashboard Help for more information on remote access. Also see the My Cloud Learning center which has information on remote access:
http://setup.wd2go.com/index.php?mod=howTo&device=mc
http://mycloud.com/learn/?id=mycloud#access-mobileapps

My cloud ■■■■■ as does WD…nopthing but problems. Trying to abandon it for MS Cloud…If I can figure out how to sync that. The engineers should all be fired at WD