diff --git a/src/services/api-service.js b/src/services/api-service.js
index fde5356..adf9912 100644
--- a/src/services/api-service.js
+++ b/src/services/api-service.js
@@ -136,6 +136,71 @@ class APIService {
     }
   }
 
+  /**
+   * Extract the useful part of an HTTP error response body.
+   * Structured WMS errors carry the diagnostic in Message / InnerException.Message —
+   * a full JSON.stringify would drown it in WatsonBuckets / HResult noise.
+   * @param {*} data - Response body (object, string, or anything axios parsed)
+   * @returns {string|null} Truncated human-readable body, or null if empty
+   */
+  _describeResponseBody(data) {
+    const MAX_BODY_LENGTH = 2000;
+    if (data == null || data === '') return null;
+    if (typeof data === 'string') return data.slice(0, MAX_BODY_LENGTH);
+    if (typeof data === 'object') {
+      const parts = [];
+      if (data.ClassName) parts.push(data.ClassName);
+      if (data.Message) parts.push(data.Message);
+      let inner = data.InnerException;
+      while (inner && inner.Message) {
+        // AggregateException répète souvent le même message dans InnerException
+        if (inner.Message !== data.Message) parts.push(`Inner: ${inner.Message}`);
+        inner = inner.InnerException;
+      }
+      const text = parts.length > 0 ? parts.join(' — ') : JSON.stringify(data);
+      return text.slice(0, MAX_BODY_LENGTH);
+    }
+    return String(data).slice(0, MAX_BODY_LENGTH);
+  }
+
+  /**
+   * Build an enriched Error from a failed HTTP call: status, verb, full URL,
+   * request payload and response body. The WMS puts the real diagnostic
+   * (compile errors, unknown entity, ...) in the response body — without this,
+   * every failure reads "Request failed with status code 500".
+   * Never includes headers (Bearer token) — payloads passed through post/get
+   * carry no credentials.
+   * @param {Error} error    - Original axios error
+   * @param {string} method  - HTTP verb ('POST' | 'GET')
+   * @param {string} url     - Full request URL
+   * @param {*} payload      - Request body (POST) or query params (GET)
+   * @returns {Error} Enriched error (original kept in .cause, status in .status)
+   */
+  _enrichHttpError(error, method, url, payload) {
+    const status = error.response?.status;
+    const parts = [`${method} ${url} failed${status != null ? ` (HTTP ${status})` : ''}: ${error.message}`];
+
+    if (payload !== undefined && payload !== null) {
+      let serialized;
+      try {
+        serialized = JSON.stringify(payload);
+      } catch {
+        serialized = String(payload);
+      }
+      if (serialized !== '{}') {
+        parts.push(`Request payload: ${serialized.slice(0, 1000)}`);
+      }
+    }
+
+    const body = this._describeResponseBody(error.response?.data);
+    if (body) parts.push(`Response body: ${body}`);
+
+    const enriched = new Error(parts.join('\n'));
+    enriched.status = status;
+    enriched.cause = error;
+    return enriched;
+  }
+
   /**
    * Make a POST request to WMS API
    * @param {string} endpoint - API endpoint (e.g., '/QueryExecute' or '/AD/api/Workflow/GetByApplication')
@@ -162,25 +227,31 @@ class APIService {
 
       return response.data;
     } catch (error) {
-      console.error(`[API] Request failed: ${error.message}`);
-
       // If unauthorized, try refreshing token and retry once
       if (error.response?.status === 401) {
         console.error('[API] Unauthorized, refreshing token and retrying...');
         await this.refreshOAuthToken();
 
-        const retryResponse = await this.httpClient.post(url, data, {
-          headers: {
-            'Authorization': `Bearer ${this.token}`,
-            'Content-Type': 'application/json',
-            'Accept': 'application/json'
-          }
-        });
+        try {
+          const retryResponse = await this.httpClient.post(url, data, {
+            headers: {
+              'Authorization': `Bearer ${this.token}`,
+              'Content-Type': 'application/json',
+              'Accept': 'application/json'
+            }
+          });
 
-        return retryResponse.data;
+          return retryResponse.data;
+        } catch (retryError) {
+          const enrichedRetry = this._enrichHttpError(retryError, 'POST', url, data);
+          console.error(`[API] Retry after token refresh failed: ${enrichedRetry.message}`);
+          throw enrichedRetry;
+        }
       }
 
-      throw error;
+      const enriched = this._enrichHttpError(error, 'POST', url, data);
+      console.error(`[API] Request failed: ${enriched.message}`);
+      throw enriched;
     }
   }
 
@@ -210,25 +281,31 @@ class APIService {
 
       return response.data;
     } catch (error) {
-      console.error(`[API] Request failed: ${error.message}`);
-
       // If unauthorized, try refreshing token and retry once
       if (error.response?.status === 401) {
         console.error('[API] Unauthorized, refreshing token and retrying...');
         await this.refreshOAuthToken();
 
-        const retryResponse = await this.httpClient.get(url, {
-          params,
-          headers: {
-            'Authorization': `Bearer ${this.token}`,
-            'Accept': 'application/json'
-          }
-        });
+        try {
+          const retryResponse = await this.httpClient.get(url, {
+            params,
+            headers: {
+              'Authorization': `Bearer ${this.token}`,
+              'Accept': 'application/json'
+            }
+          });
 
-        return retryResponse.data;
+          return retryResponse.data;
+        } catch (retryError) {
+          const enrichedRetry = this._enrichHttpError(retryError, 'GET', url, params);
+          console.error(`[API] Retry after token refresh failed: ${enrichedRetry.message}`);
+          throw enrichedRetry;
+        }
       }
 
-      throw error;
+      const enriched = this._enrichHttpError(error, 'GET', url, params);
+      console.error(`[API] Request failed: ${enriched.message}`);
+      throw enriched;
     }
   }