thanks for response, i'm not sure what's OS of azure postgres
base on my experimental with linux (centos, debian) OS support every locale but need to active it first
yeb. not standard locale is hell, i get it before, so i also with bellow list
createdb: error: database creation failed: ERROR: invalid locale name: "en-US.UTF-8"
createdb: error: database creation failed: ERROR: invalid locale name: "en-US.UTF8"
createdb: error: database creation failed: ERROR: invalid locale name: "en-US.UTF_8"
createdb: error: database creation failed: ERROR: invalid locale name: "en-US.utf-8"
createdb: error: database creation failed: ERROR: invalid locale name: "en-US.utf8"
createdb: error: database creation failed: ERROR: invalid locale name: "en-US.utf_8"
createdb: error: database creation failed: ERROR: invalid locale name: "en_US.UTF8"
createdb: error: database creation failed: ERROR: invalid locale name: "en_US.UTF-8"
createdb: error: database creation failed: ERROR: invalid locale name: "en_US.UTF_8"
createdb: error: database creation failed: ERROR: invalid locale name: "en_US.utf_8"
createdb: error: database creation failed: ERROR: invalid locale name: "en_US.utf-8"
--lc-collate en_US.utf8 --lc-ctype en_US.utf8
WARNING: Provided locale is invalid. Proceeding with collate = "en-US", ctype = "en-US"
=> this one success with warning
--lc-collate en-US --lc-ctype en-US
=> by warring change to this and success without warning
locale info is a bit difference from my server. it missing utf8 part