diff --git a/scripts/upgrade b/scripts/upgrade
index fa3f51c..39afa10 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -122,8 +122,11 @@ ynh_script_progression --message="Setting up sandobx domain: $sandboxdomain" --w
 
 # We don't test that in CI
 if ! [ ${PACKAGE_CHECK_EXEC:-0} -eq 1 ]; then
-	yunohost domain add $sandboxdomain
-	yunohost domain config set $sandboxdomain -a "mail_in=0&mail_out=0"
+	# If sandboxdomain doesn't exist, create it
+	if [ -z "$sandboxdomain" ]; then
+		yunohost domain add $sandboxdomain
+		yunohost domain config set $sandboxdomain -a "mail_in=0&mail_out=0"
+	fi
 fi
 
 #=================================================