Fix sign-in bug - add a link to the sign-in page/dialog.
The addin says I have to sign in but gives no option to do so. I am signed in to Office 365 through Edge, OneDrive, Sharepoint. So it's useless. Perhaps I'm not signed in to the right thing, in which case I'd suggest adding a link to the request to sign-in, a link that goes to the proper place so that the user can sign in.