There is no such thing as an SDMB mobile app. Try finding it in Google Play or the Apple App Store. You won’t, because it doesn’t exist. It’s a “web app” rather than a real app.
And there was yet another discussion of this issue that happened when this thread went dormant and before this zombie was revived:
The problem stemmed from the mistaken belief that this is a real mobile app that you can download when it isn’t. Most of the same answers here are seen there.