diff --git a/src/components/layout/sidebar.tsx b/src/components/layout/sidebar.tsx
index 82f5be0..d7ee87b 100644
--- a/src/components/layout/sidebar.tsx
+++ b/src/components/layout/sidebar.tsx
@@ -13,6 +13,8 @@ import {
     faCalendarCheck,
     faPhone,
     faUsers,
+    faWifi,
+    faWifiSlash,
     faArrowRightFromBracket,
     faTowerBroadcast,
     faChartLine,
@@ -32,6 +34,7 @@ import { Avatar } from "@/components/base/avatar/avatar";
 import { apiClient } from "@/lib/api-client";
 import { notify } from "@/lib/toast";
 import { useAuth } from "@/providers/auth-provider";
+import { useNetworkStatus } from "@/hooks/use-network-status";
 import { sidebarCollapsedAtom } from "@/state/sidebar-state";
 import { cx } from "@/utils/cx";
 
@@ -123,6 +126,7 @@ export const Sidebar = ({ activeUrl = "/" }: SidebarProps) => {
     const { logout, user } = useAuth();
     const navigate = useNavigate();
     const [collapsed, setCollapsed] = useAtom(sidebarCollapsedAtom);
+    const networkQuality = useNetworkStatus();
 
     const width = collapsed ? COLLAPSED_WIDTH : EXPANDED_WIDTH;
 
@@ -218,6 +222,25 @@ export const Sidebar = ({ activeUrl = "/" }: SidebarProps) => {
                 ))}
             </ul>
 
+            {/* Network indicator — only shows when network is degraded */}
+            {networkQuality !== 'good' && (
+                <div className={cx(
+                    "mx-3 mb-2 flex items-center gap-2 rounded-lg px-3 py-2 text-xs font-medium",
+                    networkQuality === 'offline'
+                        ? "bg-error-secondary text-error-primary"
+                        : "bg-warning-secondary text-warning-primary",
+                    collapsed && "justify-center mx-2 px-2",
+                )}>
+                    <FontAwesomeIcon
+                        icon={networkQuality === 'offline' ? faWifiSlash : faWifi}
+                        className="size-3.5 shrink-0"
+                    />
+                    {!collapsed && (
+                        <span>{networkQuality === 'offline' ? 'No connection' : 'Unstable network'}</span>
+                    )}
+                </div>
+            )}
+
             {/* Account card */}
             <div className={cx("mt-auto py-4", collapsed ? "flex justify-center px-2" : "px-2 lg:px-4")}>
                 {collapsed ? (
diff --git a/src/hooks/use-network-status.ts b/src/hooks/use-network-status.ts
new file mode 100644
index 0000000..e988f31
--- /dev/null
+++ b/src/hooks/use-network-status.ts
@@ -0,0 +1,46 @@
+import { useState, useEffect, useRef } from 'react';
+
+export type NetworkQuality = 'good' | 'unstable' | 'offline';
+
+export const useNetworkStatus = (): NetworkQuality => {
+    const [quality, setQuality] = useState<NetworkQuality>(navigator.onLine ? 'good' : 'offline');
+    const dropCountRef = useRef(0);
+    const resetTimerRef = useRef<number | null>(null);
+
+    useEffect(() => {
+        const handleOffline = () => {
+            console.log('[NETWORK] Offline');
+            setQuality('offline');
+        };
+
+        const handleOnline = () => {
+            console.log('[NETWORK] Back online');
+            dropCountRef.current++;
+
+            // 3+ drops in 2 minutes = unstable
+            if (dropCountRef.current >= 3) {
+                setQuality('unstable');
+            } else {
+                setQuality('good');
+            }
+
+            // Reset drop counter after 2 minutes of stability
+            if (resetTimerRef.current) clearTimeout(resetTimerRef.current);
+            resetTimerRef.current = window.setTimeout(() => {
+                dropCountRef.current = 0;
+                if (navigator.onLine) setQuality('good');
+            }, 120000);
+        };
+
+        window.addEventListener('offline', handleOffline);
+        window.addEventListener('online', handleOnline);
+
+        return () => {
+            window.removeEventListener('offline', handleOffline);
+            window.removeEventListener('online', handleOnline);
+            if (resetTimerRef.current) clearTimeout(resetTimerRef.current);
+        };
+    }, []);
+
+    return quality;
+};
diff --git a/src/lib/api-client.ts b/src/lib/api-client.ts
index 3d44bee..83ec8c4 100644
--- a/src/lib/api-client.ts
+++ b/src/lib/api-client.ts
@@ -88,6 +88,21 @@ const handleResponse = async <T>(response: Response, silent = false, retryFn?: (
 
     const json = await response.json().catch(() => null);
 
+    // Sidecar may return 400 when the underlying platform token expired — retry with refreshed token
+    if (!response.ok && retryFn) {
+        const msg = (json?.message ?? '').toLowerCase();
+        if (msg.includes('agent identity') || msg.includes('token') || msg.includes('unauthenticated')) {
+            const refreshed = await tryRefreshToken();
+            if (refreshed) {
+                const retryResponse = await retryFn();
+                return handleResponse<T>(retryResponse, silent);
+            }
+            clearTokens();
+            if (!silent) notify.error('Session expired. Please log in again.');
+            throw new AuthError();
+        }
+    }
+
     if (!response.ok) {
         const message = json?.message ?? json?.error ?? `Request failed (${response.status})`;
         if (!silent) notify.error(message);
@@ -152,7 +167,22 @@ export const apiClient = {
             }
         }
 
-        const json = await response.json();
+        let json = await response.json();
+
+        // Platform returns 200 with UNAUTHENTICATED error when token expires — retry with refresh
+        const authError = json.errors?.find((e: any) => e.extensions?.code === 'UNAUTHENTICATED');
+        if (authError) {
+            const refreshed = await tryRefreshToken();
+            if (refreshed) {
+                const retryResponse = await doFetch();
+                json = await retryResponse.json();
+            } else {
+                clearTokens();
+                if (!options?.silent) notify.error('Session expired', 'Please log in again.');
+                throw new AuthError();
+            }
+        }
+
         if (json.errors) {
             const message = json.errors[0]?.message ?? 'GraphQL error';
             if (!options?.silent) notify.error('Query failed', message);
diff --git a/src/providers/sip-provider.tsx b/src/providers/sip-provider.tsx
index f510748..9926898 100644
--- a/src/providers/sip-provider.tsx
+++ b/src/providers/sip-provider.tsx
@@ -14,27 +14,25 @@ import { registerSipStateUpdater, connectSip, disconnectSip, getSipClient, setOu
 import { apiClient } from '@/lib/api-client';
 import type { SIPConfig } from '@/types/sip';
 
-const getSipConfig = (): SIPConfig => {
+// SIP config comes exclusively from the Agent entity (stored on login).
+// No env var fallback — users without an Agent entity don't connect SIP.
+const getSipConfig = (): SIPConfig | null => {
     try {
         const stored = localStorage.getItem('helix_agent_config');
         if (stored) {
             const config = JSON.parse(stored);
-            return {
-                displayName: 'Helix Agent',
-                uri: config.sipUri,
-                password: config.sipPassword,
-                wsServer: config.sipWsServer,
-                stunServers: 'stun:stun.l.google.com:19302',
-            };
+            if (config.sipUri && config.sipWsServer) {
+                return {
+                    displayName: 'Helix Agent',
+                    uri: config.sipUri,
+                    password: config.sipPassword,
+                    wsServer: config.sipWsServer,
+                    stunServers: 'stun:stun.l.google.com:19302',
+                };
+            }
         }
     } catch {}
-    return {
-        displayName: import.meta.env.VITE_SIP_DISPLAY_NAME ?? 'Helix Agent',
-        uri: import.meta.env.VITE_SIP_URI ?? '',
-        password: import.meta.env.VITE_SIP_PASSWORD ?? '',
-        wsServer: import.meta.env.VITE_SIP_WS_SERVER ?? '',
-        stunServers: 'stun:stun.l.google.com:19302',
-    };
+    return null;
 };
 
 export const SipProvider = ({ children }: PropsWithChildren) => {
@@ -55,9 +53,14 @@ export const SipProvider = ({ children }: PropsWithChildren) => {
         });
     }, [setConnectionStatus, setCallState, setCallerNumber, setCallUcid]);
 
-    // Auto-connect SIP on mount
+    // Auto-connect SIP on mount — only if Agent entity has SIP config
     useEffect(() => {
-        connectSip(getSipConfig());
+        const config = getSipConfig();
+        if (config) {
+            connectSip(config);
+        } else {
+            console.log('[SIP] No agent SIP config — skipping connection');
+        }
     }, []);
 
     // Call duration timer
@@ -178,7 +181,7 @@ export const useSip = () => {
         isInCall: ['ringing-in', 'ringing-out', 'active'].includes(callState),
         ozonetelStatus: 'logged-in' as const,
         ozonetelError: null as string | null,
-        connect: () => connectSip(getSipConfig()),
+        connect: () => { const c = getSipConfig(); if (c) connectSip(c); },
         disconnect: disconnectSip,
         makeCall,
         dialOutbound,