[PeterWhittaker]

Any particular add-ons or features need to be disabled for this to work?

JOOC, I temporarily allowed cookies, no luck. Then disabled ABP for the domain, no luck.

[scthi]

Are you using normal GDrive or GApps? If you're using GApps then access restricted be limited by your administrator.

[PeterWhittaker]

I have two or three google IDs active most of the time, my personal gmail ID and two GApps IDs. The usual behaviour when I access anything GDrive/GApps related is that Google will either default to "first logged in" (which I try to remember to make the gmail personal ID) or will prompt me to choose from among the logged in IDs.

This app literally does nothing: I click the button, nothing happens.