diff --git a/CHANGELOG.md b/CHANGELOG.md
index faab29554..1a0113461 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,13 @@ Newest first. `Unreleased` is what is on `main` and not yet tagged.
 
 ## Unreleased
 
+### Syncing a memory source a policy refuses says why
+
+When a connected app's policy refused the read behind a memory source's sync, `POST
+/api/memory/sources/:id/sync` answered 503 "Memory is unavailable. Try again.", although the
+refusal's own sentence was already saved on the source. It now answers 400 with that sentence, as
+the plugin routes do for the same refusal.
+
 ### `@Ops Lead` in a group addresses Ops Lead, not Ops as well
 
 In a group conversation, a reply naming `@Ops Lead` also addressed a Bot called Ops, because the
diff --git a/server/src/memory/routes.ts b/server/src/memory/routes.ts
index f3733d43a..192c48ad0 100644
--- a/server/src/memory/routes.ts
+++ b/server/src/memory/routes.ts
@@ -1,6 +1,7 @@
 import { Hono, type MiddlewareHandler } from "hono";
 import { bodyLimit } from "hono/body-limit";
 import type { AppVariables } from "../auth/guards";
+import { PluginRefusedError } from "../plugins/store";
 import type { MemoryIngestion } from "./ingestion";
 import type { MemoryStore } from "./store";
 import { MemoryNotFoundError, MemoryRefusedError } from "./types";
@@ -15,7 +16,12 @@ export function createMemoryRoutes(
   routes.onError((error, context) => {
     if (error instanceof MemoryNotFoundError)
       return context.json({ error: error.message }, 404);
-    if (error instanceof MemoryRefusedError)
+    // A connector's policy refusing the read is an answer to give the person, as it is on the
+    // plugin routes, and the same sentence `sync` saves on the source.
+    if (
+      error instanceof MemoryRefusedError ||
+      error instanceof PluginRefusedError
+    )
       return context.json({ error: error.message }, 400);
     console.error(
       JSON.stringify({
diff --git a/server/tests/memory.test.ts b/server/tests/memory.test.ts
index 05989af40..988b4a797 100644
--- a/server/tests/memory.test.ts
+++ b/server/tests/memory.test.ts
@@ -1,15 +1,20 @@
 import { expect, test } from "bun:test";
 import { z } from "zod";
+import type { AuthenticatedActor } from "../src/auth/guards";
+import type { MemoryIngestion } from "../src/memory/ingestion";
 import {
   normalizeConnectorRecords,
   quoteMemoryContext,
 } from "../src/memory/ingestion";
+import { createMemoryRoutes } from "../src/memory/routes";
+import type { MemoryStore } from "../src/memory/store";
 import { memoryTools } from "../src/memory/tools";
 import {
   parseMemoryInput,
   parseMemoryPatch,
   parseMemorySourceInput,
 } from "../src/memory/types";
+import { PluginRefusedError } from "../src/plugins/store";
 
 test("memory validates explicit facts and bounded source opt-in", () => {
   expect(
@@ -137,3 +142,23 @@ test("every memory tool can be offered to a remote Bot as JSON Schema", async ()
     },
   ]);
 });
+
+test("a source sync a connector's policy refuses answers 400 with the reason, not 503", async () => {
+  const routes = createMemoryRoutes(
+    {} as MemoryStore,
+    {
+      sync: async () => {
+        throw new PluginRefusedError("Tool refused by policy.", "deny-notion");
+      },
+    } as unknown as MemoryIngestion,
+    async (context, next) => {
+      context.set("actor", { id: "person" } as AuthenticatedActor);
+      await next();
+    },
+  );
+  const response = await routes.request("/sources/source-1/sync", {
+    method: "POST",
+  });
+  expect(response.status).toBe(400);
+  expect(await response.json()).toEqual({ error: "Tool refused by policy." });
+});