diff --git a/appmanage/Dockerfile b/appmanage/Dockerfile
index 8b1d2295..7a4cb109 100644
--- a/appmanage/Dockerfile
+++ b/appmanage/Dockerfile
@@ -10,7 +10,7 @@ COPY static ./static
 COPY requirements.txt main.py database.sqlite  ./
 RUN apt update
 
-# Install supervisords
+# Install supervisord
 RUN apt install -y supervisor
 COPY config/supervisord.conf /etc/supervisor/conf.d/supervisord.conf
 COPY config/cmd.sh /cmd.sh
diff --git a/appmanage/api/service/db.py b/appmanage/api/service/db.py
index 94c2cce6..abcc1eab 100644
--- a/appmanage/api/service/db.py
+++ b/appmanage/api/service/db.py
@@ -19,7 +19,9 @@ def AppUpdateUser(user_name, password):
     conn.close()
 
 def AppSearchUsers(user_type):
-    if user_type != "nginx" or user_type != "portainer":
+    if user_type == None or user_type == "undefine":
+      raise CommandException(const.ERROR_CLIENT_PARAM_BLANK, "This plugin is blank!", "This plugin is blank!")
+    if user_type != "nginx" and user_type != "portainer":
       raise CommandException(const.ERROR_CLIENT_PARAM_NOTEXIST, "This plugin doesn't exist!", "This plugin doesn't exist!")
     conn = sqlite3.connect('/usr/src/app/database.sqlite')
     conn.row_factory = dict_factory