diff --git a/ADconnection.sh b/ADconnection.sh
index 15d70ed..93565de 100644
--- a/ADconnection.sh
+++ b/ADconnection.sh
@@ -941,6 +941,10 @@ echo ""
 echo "please type Domain admin"
 read -r ADMIN
 sudo realm join -v -U $ADMIN $DOMAIN --install=/
+if [ $? -ne 0 ]; then
+	echo "AD join failed.please check that computer object is already created and test again"
+    exit 1
+fi
 sudo systemctl start sssd
 echo "session required pam_mkhomedir.so skel=/etc/skel/ umask=0022" | sudo tee -a /etc/pam.d/common-session
 sudo echo "pi ALL=(ALL) NOPASSWD:ALL" | sudo tee -a /etc/sudoers.d/sudoers