reTurnServer: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/sbin/reTurnServer - from package: resiprocate-turn-server

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/sbin/reTurnServer - from package: resiprocate-turn-server

You may install the required package with command apt-get install {package}

Error in other languages:
reTurnServer: bevel nie gevind nie
reTurnServer: comandă negăsită
reTurnServer: comando não encontrado
reTurnServer: commande introuvable
reTurnServer: command not found
reTurnServer: käsku ei ole
reTurnServer: không tìm thấy lệnh
reTurnServer: komanda nerasta
reTurnServer: Kommando nicht gefunden.
reTurnServer: kommandot finns inte
reTurnServer: komut yok
reTurnServer: nie znaleziono polecenia
reTurnServer: níor aimsíodh an t-ordú
reTurnServer: no se encontró la orden
reTurnServer: no s'ha trobat l'ordre
reTurnServer: opdracht niet gevonden
reTurnServer: parancs nem található
reTurnServer: perintah tidak ditemukan
reTurnServer: príkaz nenájdený
reTurnServer: příkaz nenalezen
reTurnServer: команда не найдена
reTurnServer: командата не е открита
reTurnServer: 命令找不到
reTurnServer: コマンドが見つかりません