No synchronized dates. After updating to iOS13, some users cannot add calendar events on Apple mobile QQ Music. Often, many past calendar events are often lost as well. This error usually comes down to synchronization issues. If you haven't synced your calendar yet, or the synced events have a capped time.

1. Open QQ Music.

2. Click the Sync Date button to synchronize time.

3. Return to the mobile phone interface and select the QQ Music synchronization date.