Il manque aussi le tiret devant platform :
cover:
- platform: group
name: covers_all_etage
entities:
- cover.volet_chbre1_d_level_on_off_shade
- cover.volet_chbre2_level_on_off_shade
- cover.volet_chbre3_level_on_off_shade
- cover.volet_chbre4_level_on_off_shade
- platform: group
name: covers_all_rdc
entities:
- cover.volet_bso_est_level_on_off_shade
- cover.volet_bso_sud_level_on_off_shade