I have a custom VF page that uses some JS to give a different "MyProfile" page experience in a Community. It worked fine. I logged in as a customer community user and all was well. I made a change to the VF page to add two new values. I save, I preview (from Dev console) and all looks fine and I can see the two new fields. Then I log in as the customer user and get an error that the page cannot be displayed. I checked the FLS for the Customer profile and they have view access to that object and to those fields. Any idea what I might be missing? The fields added are Contact fields which I access through dot notation (User.Contact.myfieldname).