ipa-replica-conncheck: command not found

Have You tried accessing the binary with the full path?

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/ipa-replica-conncheck - from package: ipa-server

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