Can't access gsr private from iphone?.

[Gas74]

Anyone any ideas why I can't access private her forum when on my iPhone when out and about.
Input in my username and pw. But it just jumps back to normal forum.
Confused.com

 

[ShaunCorbs]

can you view this link?

http://www.ukplumbersforums.co.uk/gas-safe-registered-plumbers-only-private/

 

[Gas74]

Yes it's working now. Doesn't seem to work when I only have 3G ?