diff --git a/apps/dashboard/src/app/(dashboard)/status-pages/[id]/maintenances/(list)/page.tsx b/apps/dashboard/src/app/(dashboard)/status-pages/[id]/maintenances/(list)/page.tsx
index 75c54406f..0658fb2f5 100644
--- a/apps/dashboard/src/app/(dashboard)/status-pages/[id]/maintenances/(list)/page.tsx
+++ b/apps/dashboard/src/app/(dashboard)/status-pages/[id]/maintenances/(list)/page.tsx
@@ -3,6 +3,7 @@
 import { Button } from "@openstatus/ui/components/ui/button";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { useParams, useRouter } from "next/navigation";
+import { toast } from "sonner";
 
 import { Link } from "@/components/common/link";
 import {
@@ -18,6 +19,7 @@ import { FormSheetMaintenance } from "@/components/forms/maintenance/sheet";
 import { toCheckboxTreeItems } from "@/components/ui/checkbox-tree";
 import { DataTable } from "@/components/ui/data-table/data-table";
 import { useTRPC } from "@/lib/trpc/client";
+import { errorMessage } from "@/lib/trpc/error";
 
 export default function Page() {
   const { id } = useParams<{ id: string }>();
@@ -33,7 +35,11 @@ export default function Page() {
     }),
   );
   const sendMaintenanceUpdateMutation = useMutation(
-    trpc.subscriberNotification.maintenance.mutationOptions(),
+    trpc.subscriberNotification.maintenance.mutationOptions({
+      onError: (error) => {
+        toast.error(errorMessage(error, "Failed to notify subscribers"));
+      },
+    }),
   );
   const createMaintenanceMutation = useMutation(
     trpc.maintenance.new.mutationOptions({
diff --git a/apps/dashboard/src/app/(dashboard)/status-pages/[id]/maintenances/[maintenanceId]/client.tsx b/apps/dashboard/src/app/(dashboard)/status-pages/[id]/maintenances/[maintenanceId]/client.tsx
index 0223f4ad4..1df67cf23 100644
--- a/apps/dashboard/src/app/(dashboard)/status-pages/[id]/maintenances/[maintenanceId]/client.tsx
+++ b/apps/dashboard/src/app/(dashboard)/status-pages/[id]/maintenances/[maintenanceId]/client.tsx
@@ -50,7 +50,11 @@ export function Client({ id, pageId }: { id: number; pageId: number }) {
     toast.error(errorMessage(error, "Failed to save"));
   };
   const notify = useMutation(
-    trpc.subscriberNotification.maintenanceUpdate.mutationOptions(),
+    trpc.subscriberNotification.maintenanceUpdate.mutationOptions({
+      onError: (error) => {
+        toast.error(errorMessage(error, "Failed to notify subscribers"));
+      },
+    }),
   );
   const createUpdate = useMutation(
     trpc.maintenance.createUpdate.mutationOptions({
diff --git a/apps/dashboard/src/components/forms/maintenance/sheet-create.tsx b/apps/dashboard/src/components/forms/maintenance/sheet-create.tsx
index 16c1f9232..00384bd1d 100644
--- a/apps/dashboard/src/components/forms/maintenance/sheet-create.tsx
+++ b/apps/dashboard/src/components/forms/maintenance/sheet-create.tsx
@@ -12,6 +12,7 @@ import {
 import { Separator } from "@openstatus/ui/components/ui/separator";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { useState } from "react";
+import { toast } from "sonner";
 
 import {
   EmptyStateContainer,
@@ -30,6 +31,7 @@ import {
 import { FormMaintenance } from "@/components/forms/maintenance/form";
 import { toCheckboxTreeItems } from "@/components/ui/checkbox-tree";
 import { useTRPC } from "@/lib/trpc/client";
+import { errorMessage } from "@/lib/trpc/error";
 
 /**
  * Create-maintenance sheet with a status page selector — for surfaces that
@@ -67,7 +69,11 @@ export function FormSheetMaintenanceCreate({
   );
 
   const sendMaintenanceUpdateMutation = useMutation(
-    trpc.subscriberNotification.maintenance.mutationOptions(),
+    trpc.subscriberNotification.maintenance.mutationOptions({
+      onError: (error) => {
+        toast.error(errorMessage(error, "Failed to notify subscribers"));
+      },
+    }),
   );
   const createMaintenanceMutation = useMutation(
     trpc.maintenance.new.mutationOptions({
diff --git a/apps/server/src/routes/rpc/handlers/maintenance/__tests__/maintenance.test.ts b/apps/server/src/routes/rpc/handlers/maintenance/__tests__/maintenance.test.ts
index 51aa8bcc5..7b70ae368 100644
--- a/apps/server/src/routes/rpc/handlers/maintenance/__tests__/maintenance.test.ts
+++ b/apps/server/src/routes/rpc/handlers/maintenance/__tests__/maintenance.test.ts
@@ -396,6 +396,28 @@ describe("MaintenanceService.CreateMaintenance", () => {
     expect(res.status).toBe(404);
   });
 
+  test("rejects page component ids that are not plain decimal digits", async () => {
+    const fromDate = new Date(Date.now() + 7 * 24 * 60 * 60 * 1000);
+    const toDate = new Date(Date.now() + 7 * 24 * 60 * 60 * 1000 + 3600000);
+
+    for (const id of ["1e3", "0x10", "1.5", ""]) {
+      const res = await connectRequest(
+        "CreateMaintenance",
+        {
+          title: "Malformed component id",
+          message: "Test message",
+          from: fromDate.toISOString(),
+          to: toDate.toISOString(),
+          pageId: String(testPageId),
+          pageComponentIds: [id],
+        },
+        { "x-openstatus-key": authKey },
+      );
+      expect(res.status).toBe(400);
+      expect((await res.json()).code).toBe("invalid_argument");
+    }
+  });
+
   test("returns error when page components are from different pages", async () => {
     const fromDate = new Date(Date.now() + 7 * 24 * 60 * 60 * 1000);
     const toDate = new Date(Date.now() + 7 * 24 * 60 * 60 * 1000 + 3600000);
diff --git a/apps/server/src/routes/rpc/handlers/maintenance/index.ts b/apps/server/src/routes/rpc/handlers/maintenance/index.ts
index 85c5f17c5..fbfabad94 100644
--- a/apps/server/src/routes/rpc/handlers/maintenance/index.ts
+++ b/apps/server/src/routes/rpc/handlers/maintenance/index.ts
@@ -34,16 +34,20 @@ function parseDate(dateString: string): Date {
   return date;
 }
 
+// `Number("1e3")` is 1000 and `Number("0x10")` is 16 — both would silently
+// target another component, so only plain decimal digits are accepted.
+const PAGE_COMPONENT_ID = /^\d+$/;
+
 function parsePageComponentIds(ids: ReadonlyArray<string>): number[] {
   return ids.map((id) => {
-    const n = Number(id);
-    if (id.trim() === "" || !Number.isSafeInteger(n)) {
+    const trimmed = id.trim();
+    if (!PAGE_COMPONENT_ID.test(trimmed)) {
       throw new ConnectError(
         `Invalid page component id: "${id}"`,
         Code.InvalidArgument,
       );
     }
-    return n;
+    return Number(trimmed);
   });
 }