I am currently part of the Xbox One Update Preview, since 14th March (UK time) I have not had access to my pins or the store from my home screen. They keep timing out and coming up with 'Having trouble connecting? It may be a problem on our side. we are working on it'.
I can access my profile and have internet connectivity and pass the multiplayer test
Version 6.2.10689.0 (xb_rel_1403.140301-2200) fire
I have no access to the Xbox One Update Preview Forum either....