Florent Poittevin · Florent Poittevin · Alicia.DeDiosFuente
--- a/projects/solidify-frontend/src/lib/error-handling/global-errors-handler.service.ts
+++ b/projects/solidify-frontend/src/lib/error-handling/global-errors-handler.service.ts
-      const isErrorToTreat = ErrorHelper.isErrorToTreat(nativeError, httpErrorKeyToSkipInErrorHandler);
-      if (isErrorToTreat) {
+    const isBackendError = nativeError instanceof HttpErrorResponse;
+    if (isBackendError) {
+      const isErrorToDisplay = ErrorHelper.isErrorToDisplay(nativeError, httpErrorKeyToSkipInErrorHandler);
+      if (isErrorToDisplay) {
        // Server Error
        message = this.errorService.getServerMessage(nativeError);
-        const subMessage = nativeError.error?.message;
+        subMessage = this.errorService.getServerSubMessage(nativeError);
        stackTrace = this.errorService.getServerStack(nativeError);
        if (isNotNullNorUndefined(notifierService)) {
          notifierService.showError(message, undefined, undefined, subMessage, undefined, nativeError);
        }
+      } else {
+        // DISPLAY NOTHING TO USER
--- a/projects/solidify-frontend/src/lib/core/services/error.service.ts
+++ b/projects/solidify-frontend/src/lib/core/services/error.service.ts
    return error.message;
  }

+  getServerSubMessage(error: HttpErrorResponse): string {
+    if (error.status === HttpStatusCode.BadRequest) {
+      const listValidationErrors = ErrorHelper.extractValidationErrorsNotAlreadyDisplayedFromError(error);
+      const validationErrorsMessage = ErrorHelper.mergeValidationErrorsMessages(listValidationErrors);