notifytest: 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/bin/notifytest - from package: cyrus-imapd-utils

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

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