I recently spent a week in Italy and the Android app would only (after a long delay) load notifications. The flows and private messages never loaded even after minutes of waiting. Basically the app was unusable
I was using Elisa DataTraveller that provided 4G/3G connection where available. The mobile connection was fine for streaming videos on YouTube and browsing web/Facebook.
suchflowverywow I will open a case for you on this subject, as I would like to collect some more information on this issue.