diff --git a/web/src/authorities/authorities-page.tsx b/web/src/authorities/authorities-page.tsx
index 1ce4268..97e18a3 100644
--- a/web/src/authorities/authorities-page.tsx
+++ b/web/src/authorities/authorities-page.tsx
@@ -5,6 +5,7 @@ import { useTranslation } from "react-i18next";
 import type { components } from "../api/schema";
 import { useAuthorities, useCreateAuthority } from "../api/queries";
 import { LabelEditor } from "../components/label-editor";
+import { MutationError } from "../components/mutation-error";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -141,11 +142,7 @@ export function AuthoritiesPage() {
           </p>
         )}
 
-        {create.isError && (
-          <p role="alert" className="text-xs text-destructive">
-            {t("form.rejected")}
-          </p>
-        )}
+        <MutationError error={create.error} />
 
         <Button type="submit" size="sm" disabled={create.isPending}>
           {t("authorities.create")}
diff --git a/web/src/fields/field-form.tsx b/web/src/fields/field-form.tsx
index 4bb86e5..60afd05 100644
--- a/web/src/fields/field-form.tsx
+++ b/web/src/fields/field-form.tsx
@@ -8,6 +8,7 @@ import {
   useVocabularies,
 } from "../api/queries";
 import { LabelEditor } from "../components/label-editor";
+import { MutationError } from "../components/mutation-error";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -95,7 +96,6 @@ export function FieldForm({
   };
 
   const pending = isEdit ? update.isPending : create.isPending;
-  const failed = isEdit ? update.isError : create.isError;
 
   return (
     <form onSubmit={onSubmit} className="space-y-3 overflow-auto p-4">
@@ -198,11 +198,7 @@ export function FieldForm({
           {t("form.required")}
         </p>
       )}
-      {failed && (
-        <p role="alert" className="text-xs text-destructive">
-          {t("form.rejected")}
-        </p>
-      )}
+      <MutationError error={isEdit ? update.error : create.error} />
 
       <Button type="submit" size="sm" disabled={pending}>
         {isEdit ? t("actions.save") : t("fields.create")}
diff --git a/web/src/objects/object-edit-form.test.tsx b/web/src/objects/object-edit-form.test.tsx
index 18aed44..767bb4c 100644
--- a/web/src/objects/object-edit-form.test.tsx
+++ b/web/src/objects/object-edit-form.test.tsx
@@ -69,3 +69,15 @@ test("edit: prefilled, save -> PUT core + PUT fields -> back to detail", async (
   expect((putCore as { object_name: string }).object_name).toBe("Big amphora");
   expect((putFields as { inscription: string }).inscription).toBe("old");
 });
+
+test("renders a load error (not 'not found') when the object fetch fails", async () => {
+  server.use(http.get("/api/admin/objects/:id", () => new HttpResponse(null, { status: 500 })));
+  renderApp(
+    <Routes>
+      <Route path="/objects/:id/edit" element={<ObjectEditForm />} />
+    </Routes>,
+    { route: "/objects/abc/edit" },
+  );
+  expect(await screen.findByText(/could not load/i)).toBeInTheDocument();
+  expect(screen.queryByText(/not found/i)).toBeNull();
+});
diff --git a/web/src/objects/object-edit-form.tsx b/web/src/objects/object-edit-form.tsx
index 0677ac1..12c936a 100644
--- a/web/src/objects/object-edit-form.tsx
+++ b/web/src/objects/object-edit-form.tsx
@@ -4,6 +4,7 @@ import { useTranslation } from "react-i18next";
 
 import type { components } from "../api/schema";
 import { useObject, useUpdateObject, useSetFields, FieldRejection } from "../api/queries";
+import { errorMessageKey } from "../api/error-message";
 import { useBreadcrumb } from "../shell/use-breadcrumb";
 import { ObjectForm, type ObjectCore, type ObjectFormValues } from "./object-form";
 import { FormSkeleton } from "@/components/ui/skeletons";
@@ -14,10 +15,12 @@ export function ObjectEditForm() {
   const { t } = useTranslation();
   const { id } = useParams();
 
-  const { data: object, isLoading } = useObject(id!);
+  const { data: object, isLoading, isError } = useObject(id!);
 
   if (isLoading) return <FormSkeleton />;
 
+  if (isError) return <p className="p-4 text-sm text-destructive">{t("objects.loadError")}</p>;
+
   if (!object) return <p className="p-4 text-sm text-muted-foreground">{t("objects.notFound")}</p>;
 
   return <ObjectEditFormLoaded object={object} id={id!} />;
@@ -84,7 +87,8 @@ function ObjectEditFormLoaded({ object, id }: { object: AdminObjectView; id: str
         setFieldErrorCode(e.code);
         setError(t("form.fieldRejected", { field: e.field }));
       } else {
-        setError(t("form.rejected"));
+        const { key, opts } = errorMessageKey(e);
+        setError(t(key, opts));
       }
 
       return false;
diff --git a/web/src/objects/object-new-page.tsx b/web/src/objects/object-new-page.tsx
index 7940935..e25a580 100644
--- a/web/src/objects/object-new-page.tsx
+++ b/web/src/objects/object-new-page.tsx
@@ -4,6 +4,7 @@ import { useTranslation } from "react-i18next";
 
 import { ObjectForm, type ObjectFormValues } from "./object-form";
 import { useCreateObject, useSetFields, FieldRejection } from "../api/queries";
+import { errorMessageKey } from "../api/error-message";
 import { useDocumentTitle } from "../lib/use-document-title";
 import { useBreadcrumb } from "../shell/use-breadcrumb";
 import { PageTitle } from "@/components/ui/page-title";
@@ -33,8 +34,9 @@ export function ObjectNewPage() {
       });
 
       id = created.id;
-    } catch {
-      setError(t("form.rejected"));
+    } catch (e) {
+      const { key, opts } = errorMessageKey(e);
+      setError(t(key, opts));
       return false;
     }
 
diff --git a/web/src/vocab/vocabulary-list.tsx b/web/src/vocab/vocabulary-list.tsx
index 470dcd9..581d09b 100644
--- a/web/src/vocab/vocabulary-list.tsx
+++ b/web/src/vocab/vocabulary-list.tsx
@@ -5,6 +5,7 @@ import { useTranslation } from "react-i18next";
 import { useVocabularies, useCreateVocabulary, useRenameVocabulary, useDeleteVocabulary } from "../api/queries";
 import { byKey } from "../lib/sort";
 import { DeleteConfirmDialog } from "../components/delete-confirm-dialog";
+import { MutationError } from "../components/mutation-error";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -54,11 +55,7 @@ export function VocabularyList() {
             {t("vocab.create")}
           </Button>
         </div>
-        {create.isError && (
-          <p role="alert" className="text-xs text-destructive">
-            {t("form.rejected")}
-          </p>
-        )}
+        <MutationError error={create.error} />
       </form>
       <div className="border-b p-2">
         <Input
@@ -106,11 +103,7 @@ export function VocabularyList() {
                 <Button type="button" variant="ghost" size="sm" onClick={() => setEditingId(null)}>
                   {t("form.cancel")}
                 </Button>
-                {renameVocabulary.isError && (
-                  <p role="alert" className="text-xs text-destructive">
-                    {t("form.rejected")}
-                  </p>
-                )}
+                <MutationError error={renameVocabulary.error} />
               </form>
             ) : (
               <>
diff --git a/web/src/vocab/vocabulary-terms.tsx b/web/src/vocab/vocabulary-terms.tsx
index 3707f29..d31cc32 100644
--- a/web/src/vocab/vocabulary-terms.tsx
+++ b/web/src/vocab/vocabulary-terms.tsx
@@ -8,6 +8,7 @@ import { byLabel } from "../lib/sort";
 import { labelText } from "../lib/labels";
 import { useBreadcrumb } from "../shell/use-breadcrumb";
 import { LabelEditor } from "../components/label-editor";
+import { MutationError } from "../components/mutation-error";
 import { TermRow } from "./term-row";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
@@ -116,11 +117,7 @@ export function VocabularyTerms() {
             {t("form.required")}
           </p>
         )}
-        {addTerm.isError && (
-          <p role="alert" className="text-xs text-destructive">
-            {t("form.rejected")}
-          </p>
-        )}
+        <MutationError error={addTerm.error} />
         <Button type="submit" size="sm" disabled={addTerm.isPending}>
           {t("vocab.addTerm")}
         </Button>