diff --git a/src/lib/apiProxy.test.ts b/src/lib/apiProxy.test.ts
new file mode 100644
index 0000000..54e3d2f
--- /dev/null
+++ b/src/lib/apiProxy.test.ts
@@ -0,0 +1,52 @@
+// @vitest-environment node
+
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { NextRequest } from 'next/server'
+
+import { proxyRequestToUpstream } from './apiProxy'
+
+describe('proxyRequestToUpstream', () => {
+  afterEach(() => {
+    vi.unstubAllGlobals()
+  })
+
+  it('strips stale encoding headers when the upstream body is already decoded', async () => {
+    const fetchMock = vi.fn().mockResolvedValue(
+      new Response(JSON.stringify([{ name: 'JP', address: 'jp-xhttp.svc.plus' }]), {
+        status: 200,
+        headers: {
+          'Content-Encoding': 'gzip',
+          'Content-Length': '405',
+          'Content-Type': 'application/json; charset=utf-8',
+        },
+      }),
+    )
+    vi.stubGlobal('fetch', fetchMock)
+
+    const response = await proxyRequestToUpstream(
+      new NextRequest('https://console.svc.plus/api/agent/nodes', {
+        headers: {
+          host: 'console.svc.plus',
+        },
+      }),
+      {
+        upstreamBaseUrl: 'https://accounts.svc.plus',
+        upstreamPathPrefix: '/api/agent',
+      },
+    )
+
+    expect(fetchMock).toHaveBeenCalledWith(
+      'https://accounts.svc.plus/api/agent/nodes',
+      expect.objectContaining({
+        cache: 'no-store',
+        method: 'GET',
+        redirect: 'manual',
+      }),
+    )
+    expect(response.status).toBe(200)
+    expect(response.headers.get('content-encoding')).toBeNull()
+    expect(response.headers.get('content-length')).toBeNull()
+    expect(response.headers.get('content-type')).toBe('application/json; charset=utf-8')
+    await expect(response.json()).resolves.toEqual([{ name: 'JP', address: 'jp-xhttp.svc.plus' }])
+  })
+})
diff --git a/src/lib/apiProxy.ts b/src/lib/apiProxy.ts
index 19fff40..86d2a3a 100644
--- a/src/lib/apiProxy.ts
+++ b/src/lib/apiProxy.ts
@@ -14,6 +14,14 @@ const DEFAULT_FORWARD_HEADERS = [
   'x-trace-id',
 ] as const
 
+const RESPONSE_HEADERS_TO_STRIP = new Set([
+  'connection',
+  'content-encoding',
+  'content-length',
+  'keep-alive',
+  'transfer-encoding',
+])
+
 const BODYLESS_METHODS = new Set(['GET', 'HEAD'])
 
 type ProxyOptions = {
@@ -107,7 +115,8 @@ export async function proxyRequestToUpstream(request: NextRequest, options: Prox
 
   const responseHeaders = new Headers()
   upstreamResponse.headers.forEach((value, key) => {
-    if (key.toLowerCase() === 'set-cookie') {
+    const normalizedKey = key.toLowerCase()
+    if (normalizedKey === 'set-cookie' || RESPONSE_HEADERS_TO_STRIP.has(normalizedKey)) {
       return
     }
     responseHeaders.set(key, value)
diff --git a/src/modules/extensions/builtin/user-center/lib/fetchAgentNodes.test.ts b/src/modules/extensions/builtin/user-center/lib/fetchAgentNodes.test.ts
index caff97e..8ec685c 100644
--- a/src/modules/extensions/builtin/user-center/lib/fetchAgentNodes.test.ts
+++ b/src/modules/extensions/builtin/user-center/lib/fetchAgentNodes.test.ts
@@ -20,7 +20,7 @@ describe('fetchAgentNodes', () => {
     await expect(fetchAgentNodes()).resolves.toEqual([{ name: 'JP', address: 'jp-xhttp.svc.plus' }])
     expect(fetchMock).toHaveBeenCalledTimes(1)
     expect(fetchMock).toHaveBeenCalledWith(
-      '/api/agent-server/v1/nodes',
+      '/api/auth/sync/config?since_version=0',
       expect.objectContaining({
         cache: 'no-store',
         credentials: 'include',