Soundaria broke backward compatibility.

Make sure you use Reactive Music 1.2+.

• A lot of new music
  • Structure music
    • End City music
    • Nether Fortress music
    • Stronghold music
    • Amethyst Geode music
    • Mineshaft music
    • Ocean Monument music
    • Jungle Temple music
    • Woodland Mansion music
    • Pillager Outpost music
  • Other new music
    • Deep lava lakes music
    • Underground desert/badlands music
    • Underground snowy/icy biomes music
    • Void Blossom from Bosses of Mass Destruction mod (bosses in deep Lush caves) music
• Music volumes are equalized
• Better mod/datapack and server support
  • Now additionally to biome tags the resourcepack uses new block searcher implemented in Reactive Music 1.2.1 to determine biomes
  • It means that if the server doesn't give the information about biome or the mod/datapack that added the biome doesn't support fabric biome tags, the songpack determines the biome well