diff --git a/rsconcept/frontend/src/backend/apiTransport.ts b/rsconcept/frontend/src/backend/apiTransport.ts
index c07f9979..3e29bc54 100644
--- a/rsconcept/frontend/src/backend/apiTransport.ts
+++ b/rsconcept/frontend/src/backend/apiTransport.ts
@@ -5,6 +5,7 @@ import { AxiosError, AxiosRequestConfig } from 'axios';
 import { toast } from 'react-toastify';
 
 import { ErrorData } from '@/components/info/InfoError';
+import { extractErrorMessage } from '@/utils/utils';
 
 import { axiosInstance } from './apiConfiguration';
 
@@ -50,7 +51,7 @@ export function AxiosGet<ResponseData>({ endpoint, request, options }: IAxiosReq
     })
     .catch((error: Error | AxiosError) => {
       if (request.setLoading) request.setLoading(false);
-      if (request.showError) toast.error(error.message);
+      if (request.showError) toast.error(extractErrorMessage(error));
       if (request.onError) request.onError(error);
     });
 }
@@ -69,7 +70,7 @@ export function AxiosPost<RequestData, ResponseData>({
     })
     .catch((error: Error | AxiosError) => {
       if (request.setLoading) request.setLoading(false);
-      if (request.showError) toast.error(error.message);
+      if (request.showError) toast.error(extractErrorMessage(error));
       if (request.onError) request.onError(error);
     });
 }
@@ -88,7 +89,7 @@ export function AxiosDelete<RequestData, ResponseData>({
     })
     .catch((error: Error | AxiosError) => {
       if (request.setLoading) request.setLoading(false);
-      if (request.showError) toast.error(error.message);
+      if (request.showError) toast.error(extractErrorMessage(error));
       if (request.onError) request.onError(error);
     });
 }
@@ -108,7 +109,7 @@ export function AxiosPatch<RequestData, ResponseData>({
     })
     .catch((error: Error | AxiosError) => {
       if (request.setLoading) request.setLoading(false);
-      if (request.showError) toast.error(error.message);
+      if (request.showError) toast.error(extractErrorMessage(error));
       if (request.onError) request.onError(error);
     });
 }
diff --git a/rsconcept/frontend/src/models/ossAPI.ts b/rsconcept/frontend/src/models/ossAPI.ts
index 07dc2d4e..48bc24ba 100644
--- a/rsconcept/frontend/src/models/ossAPI.ts
+++ b/rsconcept/frontend/src/models/ossAPI.ts
@@ -31,12 +31,12 @@ export function sortItemsForOSS(oss: IOperationSchema, items: ILibraryItem[]): I
       result.push(item);
     }
   }
-  for (const item of result) {
+  for (const item of items) {
     if (item.visible && !result.includes(item)) {
       result.push(item);
     }
   }
-  for (const item of result) {
+  for (const item of items) {
     if (!result.includes(item)) {
       result.push(item);
     }
diff --git a/rsconcept/frontend/src/utils/utils.ts b/rsconcept/frontend/src/utils/utils.ts
index c16b3cd6..4a79f480 100644
--- a/rsconcept/frontend/src/utils/utils.ts
+++ b/rsconcept/frontend/src/utils/utils.ts
@@ -2,7 +2,7 @@
  * Module: Utility functions.
  */
 
-import { AxiosHeaderValue, AxiosResponse } from 'axios';
+import axios, { AxiosError, AxiosHeaderValue, AxiosResponse } from 'axios';
 
 import { prompts } from './labels';
 
@@ -139,3 +139,22 @@ export function tripleToggleColor(value: boolean | undefined): string {
   }
   return value ? 'clr-text-green' : 'clr-text-red';
 }
+
+/**
+ * Extract error message from error object.
+ */
+export function extractErrorMessage(error: Error | AxiosError): string {
+  if (axios.isAxiosError(error)) {
+    if (error.response && error.response.status === 400) {
+      const data = error.response.data as Record<string, unknown>;
+      const keys = Object.keys(data);
+      if (keys.length === 1) {
+        const value = data[keys[0]];
+        if (typeof value === 'string') {
+          return `${keys[0]}: ${value}`;
+        }
+      }
+    }
+  }
+  return error.message;
+}