User keeps getting logged out of Sugar

Hi ...One of our users keeps getting logged out of Sugar
this normally happens for one of the following reasons
1. We checked that it was not a VPN issue i.e. that the VPN was not dropping out...
2. We also checked that she was not using a shared login

...
Does anyone have any other ideas that we can try :-) any other thoughts 

Cheers and thanks
Warde