Why does the Xiaomi Watch S4 show insufficient storage when downloading/transferring songs?

The system storage is limited. To ensure the download space for other modules such as watch faces and third-party applications and the stability of the system, a module storage limit is set.
A pop-up will be prompted when one of the following conditions is triggered (whichever is reached first):
1. The number of songs exceeds 60 (a maximum of 60 songs can be downloaded);

2. The total size of audio files exceeds 2GB (including recording files, music files, etc.).