- Why do I only receive messages once I open the app?
- Which Android version is required?
- Which permissions are used under Android, and for what purpose?
- Can I buy/use Threema without a Google account?
- Why does the synchronization not work anymore after rebooting my phone?
- How can I reinstall the app without any loss of data?
- Why can’t I update the app in the Google Play Store?
- Why do I keep getting asked for the Passphrase of the Master Key?
- What does the message “Master key is unlocked” mean?
- How can I save (media) files?
- What are distribution lists?
- What is notification priority?
- What are notification channels?
- How can I customize ringtones and notification sounds?
- Xiaomi: Why is no popup displayed and no sound emitted when new messages arrive?
- What happened to “Android Backup”?
- What happened to the camera’s features?
Why does the synchronization not work anymore after rebooting my phone?
This problem only affects the Android version of Threema under specific versions of the Android operating system.
Some Android versions (Jelly Bean 4.1.1 is usually affected, and on some Samsung devices even more recent versions) have a bug that affects paid apps. The sync account is lost after rebooting the phone; consequently, the contact synchronization does not work anymore. We're currently searching for a reasonable workaround and recommend all users to update to a newer operating system version if possible.
As a temporary solution, you can turn the synchronization off and on again in the Threema settings. This will cause the account to be recreated and the synchronization will work again until the next phone reboot.
More information on this Android bug can be found here.