diff --git a/src/service/request/index.ts b/src/service/request/index.ts
index e7d6472f..638c3a9b 100644
--- a/src/service/request/index.ts
+++ b/src/service/request/index.ts
@@ -35,6 +35,7 @@ export const request = createFlatRequest<App.Service.Response, RequestInstanceSt
     },
     async onBackendFail(response, instance) {
       const authStore = useAuthStore();
+      const responseCode = String(response.data.code);
 
       function handleLogout() {
         authStore.resetStore();
@@ -49,14 +50,14 @@ export const request = createFlatRequest<App.Service.Response, RequestInstanceSt
 
       // when the backend response code is in `logoutCodes`, it means the user will be logged out and redirected to login page
       const logoutCodes = import.meta.env.VITE_SERVICE_LOGOUT_CODES?.split(',') || [];
-      if (logoutCodes.includes(response.data.code)) {
+      if (logoutCodes.includes(responseCode)) {
         handleLogout();
         return null;
       }
 
       // when the backend response code is in `modalLogoutCodes`, it means the user will be logged out by displaying a modal
       const modalLogoutCodes = import.meta.env.VITE_SERVICE_MODAL_LOGOUT_CODES?.split(',') || [];
-      if (modalLogoutCodes.includes(response.data.code) && !request.state.errMsgStack?.includes(response.data.msg)) {
+      if (modalLogoutCodes.includes(responseCode) && !request.state.errMsgStack?.includes(response.data.msg)) {
         request.state.errMsgStack = [...(request.state.errMsgStack || []), response.data.msg];
 
         // prevent the user from refreshing the page
@@ -82,7 +83,7 @@ export const request = createFlatRequest<App.Service.Response, RequestInstanceSt
       // when the backend response code is in `expiredTokenCodes`, it means the token is expired, and refresh token
       // the api `refreshToken` can not return error code in `expiredTokenCodes`, otherwise it will be a dead loop, should return `logoutCodes` or `modalLogoutCodes`
       const expiredTokenCodes = import.meta.env.VITE_SERVICE_EXPIRED_TOKEN_CODES?.split(',') || [];
-      if (expiredTokenCodes.includes(response.data.code) && !request.state.isRefreshingToken) {
+      if (expiredTokenCodes.includes(responseCode) && !request.state.isRefreshingToken) {
         request.state.isRefreshingToken = true;
 
         const refreshConfig = await handleRefreshToken(response.config);
@@ -108,7 +109,7 @@ export const request = createFlatRequest<App.Service.Response, RequestInstanceSt
       // get backend error message and code
       if (error.code === BACKEND_ERROR_CODE) {
         message = error.response?.data?.msg || message;
-        backendErrorCode = error.response?.data?.code || '';
+        backendErrorCode = String(error.response?.data?.code || '');
       }
 
       // the error message is displayed in the modal