Check if any of the following applies:

- Devices are logged into different Pioneer DJ accounts.

Use the same Pioneer DJ account on all your devices.

You can check which Pioneer DJ account you're using on each device as follows:

rekordbox for Mac/Windows: MY PAGE

rekordbox for iOS: [Settings] > [Account Information]

- Cloud Library Sync is turned off.

rekordbox for Mac/Windows: On MY PAGE, open the [LIBRARY SYNC] tab and turn on [Sync library to another device].

rekordbox for iOS: Open [Settings] > [Account Information] and turn on [Cloud Library Sync].

- You're using LINK EXPORT mode.

Libraries can't be synced when you're using LINK EXPORT mode.

When you finish using LINK EXPORT mode, the library will resume syncing.