diff --git a/litellm/proxy/_experimental/mcp_server/db.py b/litellm/proxy/_experimental/mcp_server/db.py
index 4aa08020527..cf74cbd187e 100644
--- a/litellm/proxy/_experimental/mcp_server/db.py
+++ b/litellm/proxy/_experimental/mcp_server/db.py
@@ -1600,7 +1600,7 @@ async def refresh_user_oauth_token(
 ) -> OAuthCredentialPayload | None:
     """Attempt to refresh a per-user OAuth2 token using its stored refresh_token.
 
-    POSTs to ``server.token_url`` with ``grant_type=refresh_token``.
+    POSTs to ``server.effective_token_url`` with ``grant_type=refresh_token``.
 
     On success: persists the new credential via ``store_user_oauth_credential``
     and returns the updated payload dict.
@@ -1609,7 +1609,7 @@ async def refresh_user_oauth_token(
     stale credential and triggering re-authentication.
     """
     refresh_token: Final[str | None] = cred.get("refresh_token")
-    token_url: Final[str | None] = getattr(server, "token_url", None)
+    token_url: Final[str | None] = getattr(server, "effective_token_url", None) or getattr(server, "token_url", None)
     server_id: Final[str] = getattr(server, "server_id", "")
     client_id: Final[str | None] = getattr(server, "client_id", None)
     client_secret: Final[str | None] = getattr(server, "client_secret", None)
diff --git a/litellm/proxy/_experimental/mcp_server/oauth2_token_cache.py b/litellm/proxy/_experimental/mcp_server/oauth2_token_cache.py
index c76c933c5b5..b3f1da51074 100644
--- a/litellm/proxy/_experimental/mcp_server/oauth2_token_cache.py
+++ b/litellm/proxy/_experimental/mcp_server/oauth2_token_cache.py
@@ -67,7 +67,7 @@ class MCPOAuth2TokenCache(InMemoryCache):
         rest of the identity rather than stored in a key."""
         material: Final = "\x00".join(
             (
-                server.token_url or "",
+                server.effective_token_url or "",
                 server.client_id or "",
                 server.client_secret or "",
                 " ".join(server.scopes or ()),
@@ -82,7 +82,7 @@ class MCPOAuth2TokenCache(InMemoryCache):
 
     @staticmethod
     def _has_client_credentials_config(server: "MCPServer") -> bool:
-        return bool(server.client_id and server.client_secret and server.token_url)
+        return bool(server.client_id and server.client_secret and server.effective_token_url)
 
     async def async_get_token(self, server: "MCPServer") -> str | None:
         """Return a valid access token, fetching or refreshing as needed.
@@ -112,19 +112,20 @@ class MCPOAuth2TokenCache(InMemoryCache):
             return token
 
     async def _fetch_token(self, server: "MCPServer") -> tuple[str, int]:
-        """POST to ``token_url`` with ``grant_type=client_credentials``.
+        """POST to ``effective_token_url`` with ``grant_type=client_credentials``.
 
         Returns ``(access_token, ttl_seconds)`` where ttl accounts for the
         expiry buffer so the cache entry expires before the real token does.
         """
         client: Final = get_async_httpx_client(llm_provider=httpxSpecialProvider.MCP)
 
-        if not server.client_id or not server.client_secret or not server.token_url:
+        token_url: Final = server.effective_token_url
+        if not server.client_id or not server.client_secret or not token_url:
             raise ValueError(
                 f"MCP server '{server.server_id}' missing required OAuth2 fields: "
                 f"client_id={bool(server.client_id)}, "
                 f"client_secret={bool(server.client_secret)}, "
-                f"token_url={bool(server.token_url)}"
+                f"token_url={bool(token_url)}"
             )
 
         token_request: Final = build_upstream_oauth2_token_request(
@@ -146,7 +147,7 @@ class MCPOAuth2TokenCache(InMemoryCache):
         )
 
         try:
-            response: Final = await client.post(server.token_url, data=data, headers=token_request.headers or None)
+            response: Final = await client.post(token_url, data=data, headers=token_request.headers or None)
             response.raise_for_status()
         except httpx.HTTPStatusError as exc:
             raise ValueError(
diff --git a/litellm/proxy/_experimental/mcp_server/outbound_credentials/adapter.py b/litellm/proxy/_experimental/mcp_server/outbound_credentials/adapter.py
index be8ec1b8eb3..98e239b1d1d 100644
--- a/litellm/proxy/_experimental/mcp_server/outbound_credentials/adapter.py
+++ b/litellm/proxy/_experimental/mcp_server/outbound_credentials/adapter.py
@@ -142,7 +142,7 @@ def _client_credentials_spec(server: MCPServer, resource: str) -> ServerSpec:
         config=ClientCredentialsConfig(
             client_id=server.client_id,
             client_secret=SecretStr(server.client_secret) if server.client_secret else None,
-            token_url=server.token_url,
+            token_url=server.effective_token_url,
             scopes=tuple(server.scopes or ()),
             audience=server.audience,
             upstream_resource=resolve_upstream_resource(server),
@@ -163,7 +163,7 @@ def _token_exchange_spec(server: MCPServer, resource: str) -> ServerSpec | None:
     normalizes to ``rfc8693`` so a bad config value cannot crash spec-building. ``audience`` is
     forwarded only when the operator set it; a missing one is omitted, not derived.
     """
-    endpoint: Final = server.token_exchange_endpoint or server.token_url
+    endpoint: Final = server.token_exchange_endpoint or server.effective_token_url
     if not server.client_id or not server.client_secret:
         return None
     profile: Final[Literal["rfc8693", "entra_obo"]] = (
diff --git a/litellm/proxy/_experimental/mcp_server/outbound_credentials/authz_code_refresher.py b/litellm/proxy/_experimental/mcp_server/outbound_credentials/authz_code_refresher.py
index 6ea5756d43d..92bd30694af 100644
--- a/litellm/proxy/_experimental/mcp_server/outbound_credentials/authz_code_refresher.py
+++ b/litellm/proxy/_experimental/mcp_server/outbound_credentials/authz_code_refresher.py
@@ -88,7 +88,10 @@ class AuthorizationCodeRefresher:
         if token.refresh_token is None:
             return None
         server: Final = self._server_lookup(server_id)
-        if server is None or not server.token_url:
+        if server is None:
+            return None
+        token_url: Final = server.effective_token_url
+        if not token_url:
             return None
 
         try:
@@ -106,7 +109,7 @@ class AuthorizationCodeRefresher:
             "refresh_token": token.refresh_token,
             **token_request.body,
         }
-        body: Final = await self._token_endpoint(server.token_url, form, token_request.headers)
+        body: Final = await self._token_endpoint(token_url, form, token_request.headers)
         if body is None:
             return None
         access_token: Final = body.get("access_token")
diff --git a/tests/test_litellm/proxy/_experimental/mcp_server/outbound_credentials/test_adapter.py b/tests/test_litellm/proxy/_experimental/mcp_server/outbound_credentials/test_adapter.py
index e336bdc80c2..0020dbf8d61 100644
--- a/tests/test_litellm/proxy/_experimental/mcp_server/outbound_credentials/test_adapter.py
+++ b/tests/test_litellm/proxy/_experimental/mcp_server/outbound_credentials/test_adapter.py
@@ -579,3 +579,22 @@ def test_id_jag_honors_explicit_subject_token_type():
 def test_id_jag_half_configured_defers_to_v1(server):
     # A half-configured server must defer (None) rather than 500 at IdJagConfig construction.
     assert to_server_spec(server) is None
+
+
+def test_client_credentials_uses_admin_entered_token_url_when_issuer_yield_empties_resolved():
+    """A pinned issuer empties the resolved token_url while configured_token_url keeps the
+    admin-entered value; the M2M spec must carry it so egress can mint."""
+    spec = to_server_spec(
+        _server(
+            auth_type=MCPAuth.oauth2,
+            oauth2_flow="client_credentials",
+            url="https://up.example.com/mcp",
+            token_url=None,
+            configured_token_url="https://idp.example.com/token",
+            client_id="cid",
+            client_secret="csec",
+        )
+    )
+    assert spec is not None
+    assert isinstance(spec.config, ClientCredentialsConfig)
+    assert spec.config.token_url == "https://idp.example.com/token"
diff --git a/tests/test_litellm/proxy/_experimental/mcp_server/outbound_credentials/test_authz_code_refresher.py b/tests/test_litellm/proxy/_experimental/mcp_server/outbound_credentials/test_authz_code_refresher.py
index ab414d1e8a4..bb2f2ff8b02 100644
--- a/tests/test_litellm/proxy/_experimental/mcp_server/outbound_credentials/test_authz_code_refresher.py
+++ b/tests/test_litellm/proxy/_experimental/mcp_server/outbound_credentials/test_authz_code_refresher.py
@@ -20,8 +20,10 @@ class _Server:
         upstream_resource=None,
         url=None,
         server_id="srv",
+        configured_token_url=None,
     ):
         self.token_url = token_url
+        self.configured_token_url = configured_token_url
         self.client_id = client_id
         self.client_secret = client_secret
         self.token_endpoint_auth_method = token_endpoint_auth_method
@@ -29,6 +31,10 @@ class _Server:
         self.url = url
         self.server_id = server_id
 
+    @property
+    def effective_token_url(self):
+        return self.token_url or self.configured_token_url
+
 
 def _lookup(server):
     return lambda server_id: server
@@ -262,3 +268,22 @@ async def test_returned_scope_overrides_prior_when_present():
     assert token is not None
     assert token.scopes == ("read",)  # a present scope replaces the prior grant
     assert persisted[0][5] == ("read",)
+
+
+@pytest.mark.asyncio
+async def test_refresh_uses_admin_entered_token_url_when_issuer_yield_empties_resolved():
+    """A pinned issuer empties the resolved token_url while configured_token_url keeps the
+    admin-entered value; the refresh grant must POST there instead of silently failing."""
+    posted = []
+    refresher = _refresher(
+        server=_Server(token_url=None, configured_token_url="https://idp.example.com/token"),
+        body={"access_token": "new-at", "expires_in": 3600},
+        post_sink=posted,
+    )
+    token = await refresher.refresh(
+        "alice", "srv", OAuthToken(access_token="old", refresh_token="old-rt")
+    )
+
+    assert token is not None
+    assert token.access_token == "new-at"
+    assert posted[0][0] == "https://idp.example.com/token"
diff --git a/tests/test_litellm/proxy/_experimental/mcp_server/test_db_credentials.py b/tests/test_litellm/proxy/_experimental/mcp_server/test_db_credentials.py
index 50248e95ffa..4d9142ad4c5 100644
--- a/tests/test_litellm/proxy/_experimental/mcp_server/test_db_credentials.py
+++ b/tests/test_litellm/proxy/_experimental/mcp_server/test_db_credentials.py
@@ -1337,3 +1337,28 @@ def test_mcp_oauth_token_identity_changes_when_only_upstream_resource_is_edited(
     assert mcp_oauth_token_identity(set_to_explicit) == mcp_oauth_token_identity(
         _identity_server(credentials={**creds, "upstream_resource": "api://audience-one"})
     )
+
+
+@pytest.mark.asyncio
+async def test_refresh_user_oauth_token_uses_admin_entered_token_url_when_issuer_yield_empties_resolved(monkeypatch):
+    """A pinned issuer empties the resolved token_url while configured_token_url keeps the
+    admin-entered value; the silent per-user refresh must POST there instead of bailing."""
+    from litellm.proxy._types import MCPTransport
+    from litellm.types.mcp import MCPAuth
+    from litellm.types.mcp_server.mcp_server_manager import MCPServer
+
+    server = MCPServer(
+        server_id="srv-1",
+        name="test",
+        url="https://up.example.com/mcp",
+        transport=MCPTransport.http,
+        auth_type=MCPAuth.oauth2,
+        client_id="cid",
+        client_secret="csec",
+        token_url=None,
+        configured_token_url="https://idp.example.com/token",
+    )
+    result, captured = await _run_refresh(monkeypatch, server)
+
+    assert result is not None
+    assert captured["url"] == "https://idp.example.com/token"
diff --git a/tests/test_litellm/proxy/_experimental/mcp_server/test_oauth2_token_cache.py b/tests/test_litellm/proxy/_experimental/mcp_server/test_oauth2_token_cache.py
index 72589fd8b3e..b1aa16a30c0 100644
--- a/tests/test_litellm/proxy/_experimental/mcp_server/test_oauth2_token_cache.py
+++ b/tests/test_litellm/proxy/_experimental/mcp_server/test_oauth2_token_cache.py
@@ -392,3 +392,22 @@ async def test_invalidate_clears_every_identity_for_a_server():
 
     assert refetched == "tok-after-invalidate"
     assert mock_client.post.call_count == 3
+
+
+@pytest.mark.asyncio
+async def test_m2m_mint_uses_admin_entered_token_url_when_issuer_yield_empties_resolved():
+    """A pinned issuer empties the resolved token_url while configured_token_url keeps the
+    admin-entered value; the client_credentials mint must POST there instead of raising."""
+    server = _server(token_url=None, configured_token_url="https://auth.example.com/token")
+    cache = MCPOAuth2TokenCache()
+    mock_client = AsyncMock()
+    mock_client.post.return_value = _token_response("m2m-token-configured")
+
+    with patch(
+        "litellm.proxy._experimental.mcp_server.oauth2_token_cache.get_async_httpx_client",
+        return_value=mock_client,
+    ):
+        result = await cache.async_get_token(server)
+
+    assert result == "m2m-token-configured"
+    assert mock_client.post.call_args[0][0] == "https://auth.example.com/token"