I'm using a Galaxy Note 10.1 with Collector for ArcGIS, and an on-premise version of Portal for ArcGIS 10.3. The wifi connection I have for our internal network is LAN only, no internet. I get as far as signing in, and can see the organisation description page, but none of the maps or groups are listed, they just get stuck on loading screen. Some webmaps in the Portal use use external basemaps, but some are completely internal.
I can access the Portal through the web browser on the same wifi connection, maps and groups are listed at least.
I'm thinking maybe a network/firewall issue which I may have to work through with our network guys, certain protocols/ports blocked? Anyone out there hit this before?