diff --git a/002_source/cms/src/components/dashboard/overview/summary/ActiveUserCount/index.tsx b/002_source/cms/src/components/dashboard/overview/summary/ActiveUserCount/index.tsx
index 520ba73..e571cab 100644
--- a/002_source/cms/src/components/dashboard/overview/summary/ActiveUserCount/index.tsx
+++ b/002_source/cms/src/components/dashboard/overview/summary/ActiveUserCount/index.tsx
@@ -1,11 +1,10 @@
 'use client';
 
 /*
-# PROMPT
+RULES:
 
-this is a subset of a typescript project
-
-clone `LessonTypeCount`, `LessonCategoriesCount` to `UserCount` and do modifiy to get the count of users, thanks.
+show loading when fetching record from db
+show error when fetch record failed
 */
 import * as React from 'react';
 import getAllUserMetasCount from '@/db/UserMetas/GetAllCount';
@@ -15,6 +14,7 @@ import { useTranslation } from 'react-i18next';
 import { Summary } from '@/components/dashboard/overview/summary';
 
 import { LoadingSummary } from '../LoadingSummary';
+import { ErrorSummary } from '../ErrorSummary';
 
 function ActiveUserCount(): React.JSX.Element {
   const { t } = useTranslation();
@@ -50,7 +50,15 @@ function ActiveUserCount(): React.JSX.Element {
     );
   }
 
-  if (showError) return <div>{errorDetail}</div>;
+  if (showError)
+    return (
+      <ErrorSummary
+        diff={10}
+        icon={UsersIcon}
+        title={t('用戶數量')}
+        trend="up"
+      />
+    );
 
   return (
     <Summary
diff --git a/002_source/cms/src/components/dashboard/overview/summary/ErrorSummary/index.tsx b/002_source/cms/src/components/dashboard/overview/summary/ErrorSummary/index.tsx
new file mode 100644
index 0000000..c014450
--- /dev/null
+++ b/002_source/cms/src/components/dashboard/overview/summary/ErrorSummary/index.tsx
@@ -0,0 +1,99 @@
+'use client';
+
+/*
+# NOTES:
+Show error to user when loading error,
+use together with:
+
+- src/components/dashboard/overview/summary/ActiveUserCount/index.tsx
+*/
+import * as React from 'react';
+import Avatar from '@mui/material/Avatar';
+import Box from '@mui/material/Box';
+import Card from '@mui/material/Card';
+import CardContent from '@mui/material/CardContent';
+import Divider from '@mui/material/Divider';
+import Stack from '@mui/material/Stack';
+import Typography from '@mui/material/Typography';
+import type { Icon } from '@phosphor-icons/react/dist/lib/types';
+import { TrendDown as TrendDownIcon } from '@phosphor-icons/react/dist/ssr/TrendDown';
+import { TrendUp as TrendUpIcon } from '@phosphor-icons/react/dist/ssr/TrendUp';
+import { useTranslation } from 'react-i18next';
+
+export interface SummaryProps {
+  diff: number;
+  icon: Icon;
+  title: string;
+  trend: 'up' | 'down';
+}
+
+export function ErrorSummary({ diff, icon: Icon, title, trend }: SummaryProps): React.JSX.Element {
+  const { t } = useTranslation();
+  return (
+    <Card>
+      <CardContent>
+        <Stack
+          direction="row"
+          spacing={3}
+          sx={{ alignItems: 'center' }}
+        >
+          <Avatar
+            sx={{
+              '--Avatar-size': '48px',
+              bgcolor: 'var(--mui-palette-background-paper)',
+              boxShadow: 'var(--mui-shadows-8)',
+              color: 'var(--mui-palette-text-primary)',
+            }}
+          >
+            <Icon fontSize="var(--icon-fontSize-lg)" />
+          </Avatar>
+          <div>
+            <Typography
+              color="text.secondary"
+              variant="body1"
+            >
+              {title}
+            </Typography>
+            <Typography variant="h3">Error</Typography>
+          </div>
+        </Stack>
+      </CardContent>
+      <Divider />
+      <Box sx={{ p: '16px' }}>
+        <Stack
+          direction="row"
+          spacing={1}
+          sx={{ alignItems: 'center' }}
+        >
+          <Box
+            sx={{
+              alignItems: 'center',
+              color: trend === 'up' ? 'var(--mui-palette-success-main)' : 'var(--mui-palette-error-main)',
+              display: 'flex',
+              justifyContent: 'center',
+            }}
+          >
+            {trend === 'up' ? (
+              <TrendUpIcon fontSize="var(--icon-fontSize-md)" />
+            ) : (
+              <TrendDownIcon fontSize="var(--icon-fontSize-md)" />
+            )}
+          </Box>
+          <Typography
+            color="text.secondary"
+            variant="body2"
+          >
+            <Typography
+              color={trend === 'up' ? 'success.main' : 'error.main'}
+              component="span"
+              variant="subtitle2"
+            >
+              {new Intl.NumberFormat('en-US', { style: 'percent', maximumFractionDigits: 2 }).format(diff / 100)}
+            </Typography>{' '}
+            {trend === 'up' ? t('increase') : t('decrease')} {t('vs last month')}
+          </Typography>
+        </Stack>
+      </Box>
+    </Card>
+  );
+}
diff --git a/002_source/cms/src/components/dashboard/overview/summary/LessonCategoriesCount/index.tsx b/002_source/cms/src/components/dashboard/overview/summary/LessonCategoriesCount/index.tsx
index 6993e41..56d2816 100644
--- a/002_source/cms/src/components/dashboard/overview/summary/LessonCategoriesCount/index.tsx
+++ b/002_source/cms/src/components/dashboard/overview/summary/LessonCategoriesCount/index.tsx
@@ -15,6 +15,7 @@ import { useTranslation } from 'react-i18next';
 import { Summary } from '@/components/dashboard/overview/summary';
 
 import { LoadingSummary } from '../LoadingSummary';
+import { ErrorSummary } from '../ErrorSummary';
 
 function LessonCategoriesCount(): React.JSX.Element {
   const { t } = useTranslation();
@@ -40,10 +41,26 @@ function LessonCategoriesCount(): React.JSX.Element {
   }, []);
 
   if (showLoading) {
-    return <LoadingSummary diff={10} icon={ListChecksIcon} title={t('用戶數量')} trend="up" />;
+    return (
+      <LoadingSummary
+        diff={10}
+        icon={ListChecksIcon}
+        title={t('用戶數量')}
+        trend="up"
+      />
+    );
   }
 
-  if (showError) return <div>{errorDetail}</div>;
+  if (showError) {
+    return (
+      <ErrorSummary
+        icon={ListChecksIcon}
+        title={t('Error')}
+        diff={0}
+        trend="down"
+      />
+    );
+  }
 
   return (
     <Summary
diff --git a/002_source/cms/src/components/dashboard/overview/summary/LessonTypeCount/index.tsx b/002_source/cms/src/components/dashboard/overview/summary/LessonTypeCount/index.tsx
index 5623204..fb41d85 100644
--- a/002_source/cms/src/components/dashboard/overview/summary/LessonTypeCount/index.tsx
+++ b/002_source/cms/src/components/dashboard/overview/summary/LessonTypeCount/index.tsx
@@ -1,5 +1,11 @@
 'use client';
 
+/*
+RULES:
+
+show loading when fetching record from db
+show error when fetch record failed
+*/
 import * as React from 'react';
 import GetAllCount from '@/db/LessonTypes/GetAllCount.tsx';
 import { ListChecks as ListChecksIcon } from '@phosphor-icons/react/dist/ssr/ListChecks';
@@ -7,6 +13,7 @@ import { useTranslation } from 'react-i18next';
 
 import { Summary } from '@/components/dashboard/overview/summary';
 import { LoadingSummary } from '@/components/dashboard/overview/summary/LoadingSummary';
+import { ErrorSummary } from '@/components/dashboard/overview/summary/ErrorSummary';
 
 function LessonTypeCount(): React.JSX.Element {
   const { t } = useTranslation();
@@ -42,11 +49,10 @@ function LessonTypeCount(): React.JSX.Element {
 
   if (error) {
     return (
-      <Summary
-        amount={0}
+      <ErrorSummary
         diff={0}
         icon={ListChecksIcon}
-        title={t('Error')}
+        title={t('課程類型')}
         trend="down"
       />
     );
diff --git a/002_source/cms/src/components/dashboard/overview/summary/index.tsx b/002_source/cms/src/components/dashboard/overview/summary/index.tsx
index 9c381d4..eaa8513 100644
--- a/002_source/cms/src/components/dashboard/overview/summary/index.tsx
+++ b/002_source/cms/src/components/dashboard/overview/summary/index.tsx
@@ -1,5 +1,11 @@
 'use client';
 
+/*
+NOTES:
+show loading when loading summary
+use with:
+- src/components/dashboard/overview/summary/ActiveUserCount/index.tsx
+*/
 import * as React from 'react';
 import Avatar from '@mui/material/Avatar';
 import Box from '@mui/material/Box';
@@ -26,7 +32,11 @@ export function Summary({ amount, diff, icon: Icon, title, trend }: SummaryProps
   return (
     <Card>
       <CardContent>
-        <Stack direction="row" spacing={3} sx={{ alignItems: 'center' }}>
+        <Stack
+          direction="row"
+          spacing={3}
+          sx={{ alignItems: 'center' }}
+        >
           <Avatar
             sx={{
               '--Avatar-size': '48px',
@@ -38,7 +48,10 @@ export function Summary({ amount, diff, icon: Icon, title, trend }: SummaryProps
             <Icon fontSize="var(--icon-fontSize-lg)" />
           </Avatar>
           <div>
-            <Typography color="text.secondary" variant="body1">
+            <Typography
+              color="text.secondary"
+              variant="body1"
+            >
               {title}
             </Typography>
             <Typography variant="h3">{new Intl.NumberFormat('en-US').format(amount)}</Typography>
@@ -47,7 +60,11 @@ export function Summary({ amount, diff, icon: Icon, title, trend }: SummaryProps
       </CardContent>
       <Divider />
       <Box sx={{ p: '16px' }}>
-        <Stack direction="row" spacing={1} sx={{ alignItems: 'center' }}>
+        <Stack
+          direction="row"
+          spacing={1}
+          sx={{ alignItems: 'center' }}
+        >
           <Box
             sx={{
               alignItems: 'center',
@@ -62,8 +79,15 @@ export function Summary({ amount, diff, icon: Icon, title, trend }: SummaryProps
               <TrendDownIcon fontSize="var(--icon-fontSize-md)" />
             )}
           </Box>
-          <Typography color="text.secondary" variant="body2">
-            <Typography color={trend === 'up' ? 'success.main' : 'error.main'} component="span" variant="subtitle2">
+          <Typography
+            color="text.secondary"
+            variant="body2"
+          >
+            <Typography
+              color={trend === 'up' ? 'success.main' : 'error.main'}
+              component="span"
+              variant="subtitle2"
+            >
               {new Intl.NumberFormat('en-US', { style: 'percent', maximumFractionDigits: 2 }).format(diff / 100)}
             </Typography>{' '}
             {trend === 'up' ? t('increase') : t('decrease')} {t('vs last month')}