turnutils_peer: 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 Debian possible default full paths are:

/usr/bin/turnutils_peer - from package: coturn
/usr/bin/turnutils_peer - from package: rfc5766-turn-server

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

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