plainbox-trusted-launcher-1: 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/plainbox-trusted-launcher-1 - from package: python3-plainbox

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

Error in other languages:
plainbox-trusted-launcher-1: bevel nie gevind nie
plainbox-trusted-launcher-1: comandă negăsită
plainbox-trusted-launcher-1: comando não encontrado
plainbox-trusted-launcher-1: commande introuvable
plainbox-trusted-launcher-1: command not found
plainbox-trusted-launcher-1: käsku ei ole
plainbox-trusted-launcher-1: không tìm thấy lệnh
plainbox-trusted-launcher-1: komanda nerasta
plainbox-trusted-launcher-1: Kommando nicht gefunden.
plainbox-trusted-launcher-1: kommandot finns inte
plainbox-trusted-launcher-1: komut yok
plainbox-trusted-launcher-1: nie znaleziono polecenia
plainbox-trusted-launcher-1: níor aimsíodh an t-ordú
plainbox-trusted-launcher-1: no se encontró la orden
plainbox-trusted-launcher-1: no s'ha trobat l'ordre
plainbox-trusted-launcher-1: opdracht niet gevonden
plainbox-trusted-launcher-1: parancs nem található
plainbox-trusted-launcher-1: perintah tidak ditemukan
plainbox-trusted-launcher-1: príkaz nenájdený
plainbox-trusted-launcher-1: příkaz nenalezen
plainbox-trusted-launcher-1: команда не найдена
plainbox-trusted-launcher-1: командата не е открита
plainbox-trusted-launcher-1: 命令找不到
plainbox-trusted-launcher-1: コマンドが見つかりません