User is getting "view only" message when working on portfolio from home

It seems completely unlikely that where the user signs in from afrects their permissions.

 I suggest that you have the user confirm that they are actually signed in to the app. They should look at the top right corner to see if they are signed in.

it is possible that they are using an app which is open to everyone on the Internet in View mode,  mode, but in order to edit they need to sign in.