After we push an update, some Android phones will get into an out-of-sync condition, causing their Visibook app to get stuck on the initial loading screen, like this:
The fix for this is simple. Just follow these steps (it might vary a little from one Android phone model to another, but these are the general steps):
Go to your phone's Android settings
Clear data and cache. Don't worry, your data will not get lost.
Restart the Visibook app and you should be all set!