When you arrive on the "enter your code" page on Android, this page may turn white if your Android goes to sleep or if you see another application in the meantime. This is a known bug that will be fixed in our next release. For now, if you have a blank page when you want to enter the code received by email, exit and relaunch Wakatoon, ask for a code again, but check your mail on a desktop, not on your mobile. Then you will be able to enter the code.
If you need more help, write by email to