You have to download sleep sounds in music mode. You can't download sleep sounds in sleep mode and importing third-party audio sources is not supported. 

To download sleep sounds, follow these steps:

1. Download sleep sounds in Bluetooth mode. 

Note: You can't download sleep sounds in Sleep mode and importing third-party audio sources is not supported.

2. The sleep sounds can be downloaded in 4 combinations, with up to three combinations of sleep sounds sources per group.

If you have any more issues or your issue has not been resolved, please contact us for further assistance.