diff --git a/server/handlers/homepage.go b/server/handlers/homepage.go
index 34e2a4a..88730fd 100644
--- a/server/handlers/homepage.go
+++ b/server/handlers/homepage.go
@@ -47,6 +47,11 @@ func GetWebHomepage(c *gin.Context) {
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 
+	if config.MongoClient == nil {
+		c.JSON(http.StatusOK, defaultHomepageData())
+		return
+	}
+
 	siteID := getOfficialSiteID(ctx)
 	if siteID == "" {
 		c.JSON(http.StatusOK, defaultHomepageData())
diff --git a/server/handlers/web_routes.go b/server/handlers/web_routes.go
index 2df4a33..337ead0 100644
--- a/server/handlers/web_routes.go
+++ b/server/handlers/web_routes.go
@@ -35,6 +35,11 @@ func GetWebRoutes(c *gin.Context) {
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 
+	if config.MongoClient == nil {
+		c.JSON(http.StatusOK, gin.H{"site_id": "", "routes": []any{}})
+		return
+	}
+
 	siteID := c.Query("site_id")
 	if siteID == "" {
 		siteID = getOfficialSiteID(ctx)
@@ -84,6 +89,11 @@ func GetWebPageByPath(c *gin.Context) {
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 
+	if config.MongoClient == nil {
+		c.JSON(http.StatusServiceUnavailable, gin.H{"error": "服务暂不可用"})
+		return
+	}
+
 	siteID := c.Query("site_id")
 	if siteID == "" {
 		siteID = getOfficialSiteID(ctx)
diff --git a/server/pkg/weblive/hub.go b/server/pkg/weblive/hub.go
index eb8b43e..747183e 100644
--- a/server/pkg/weblive/hub.go
+++ b/server/pkg/weblive/hub.go
@@ -154,7 +154,7 @@ func (h *Hub) onPublisherTrack(track *webrtc.TrackRemote) {
 	h.mu.Lock()
 	h.forwarders = append(h.forwarders, tf)
 	h.mu.Unlock()
-	go tf.runReadLoop()
+	goSafe("trackRead", tf.runReadLoop)
 	// 观众仅在「已开播」后拉流：首次协商时 attachForwardersToViewerPC 会带上当前全部轨，无需在此重协商
 }
 
@@ -173,14 +173,14 @@ func (h *Hub) attachForwardersToViewerPC(v *viewerSession) {
 			continue
 		}
 		// Drain RTCP feedback to keep interceptors/senders healthy.
-		go func() {
+		goSafe("viewerRTCP", func() {
 			rtcpBuf := make([]byte, 1500)
 			for {
 				if _, _, e := rtpSender.Read(rtcpBuf); e != nil {
 					return
 				}
 			}
-		}()
+		})
 		tf.addViewer(v.id, lt)
 	}
 }
diff --git a/server/pkg/weblive/safe.go b/server/pkg/weblive/safe.go
new file mode 100644
index 0000000..588ba6b
--- /dev/null
+++ b/server/pkg/weblive/safe.go
@@ -0,0 +1,15 @@
+package weblive
+
+import "log"
+
+// goSafe 在独立 goroutine 中运行 fn；panic 只记录日志，避免拖垮整个 HTTP 进程（否则 Nginx 会看到 502）。
+func goSafe(label string, fn func()) {
+	go func() {
+		defer func() {
+			if r := recover(); r != nil {
+				log.Printf("weblive: panic in %s: %v", label, r)
+			}
+		}()
+		fn()
+	}()
+}
diff --git a/server/pkg/weblive/ws.go b/server/pkg/weblive/ws.go
index 9357abb..d34fbba 100644
--- a/server/pkg/weblive/ws.go
+++ b/server/pkg/weblive/ws.go
@@ -120,7 +120,8 @@ func handlePublisherWS(c *gin.Context, h *Hub) {
 		log.Printf("weblive: publisher track kind=%s", track.Kind().String())
 		h.onPublisherTrack(track)
 		if track.Kind() == webrtc.RTPCodecTypeVideo {
-			go func(ssrc uint32) {
+			ssrc := uint32(track.SSRC())
+			goSafe("publisherPLI", func() {
 				_ = pc.WriteRTCP([]rtcp.Packet{&rtcp.PictureLossIndication{MediaSSRC: ssrc}})
 				ticker := time.NewTicker(2 * time.Second)
 				defer ticker.Stop()
@@ -131,7 +132,7 @@ func handlePublisherWS(c *gin.Context, h *Hub) {
 					}
 					_ = pc.WriteRTCP([]rtcp.Packet{&rtcp.PictureLossIndication{MediaSSRC: ssrc}})
 				}
-			}(uint32(track.SSRC()))
+			})
 		}
 	})
 
diff --git a/web/src/utils/liveWebRTC.js b/web/src/utils/liveWebRTC.js
index aa004d6..2368f12 100644
--- a/web/src/utils/liveWebRTC.js
+++ b/web/src/utils/liveWebRTC.js
@@ -14,10 +14,14 @@ export function liveWsURLView() {
 
 export async function fetchLiveStatus() {
   const url = apiBase ? `${apiBase}/api/web/live/status` : '/api/web/live/status'
-  const res = await fetch(url)
-  if (!res.ok) return { live: false }
-  const j = await res.json()
-  return { live: Boolean(j.live) }
+  try {
+    const res = await fetch(url)
+    if (!res.ok) return { live: false, upstreamError: true }
+    const j = await res.json()
+    return { live: Boolean(j.live), upstreamError: false }
+  } catch {
+    return { live: false, upstreamError: true }
+  }
 }
 
 const defaultIce = [{ urls: 'stun:stun.l.google.com:19302' }]
@@ -42,9 +46,17 @@ export function startViewing(videoEl, opts = {}) {
   })
   let ws = null
   let pollTimer = null
+  let currentPollMs = pollMs
   let stopped = false
   let blackFrameTimer = null
 
+  function schedulePollLoop() {
+    if (pollTimer) clearInterval(pollTimer)
+    pollTimer = null
+    if (stopped) return
+    pollTimer = setInterval(poll, currentPollMs)
+  }
+
   function clearBlackFrameTimer() {
     if (blackFrameTimer) {
       clearTimeout(blackFrameTimer)
@@ -96,7 +108,8 @@ export function startViewing(videoEl, opts = {}) {
     if (tip) onStatus(tip)
     if (pollTimer) return
     rebuildPeer()
-    pollTimer = setInterval(poll, pollMs)
+    currentPollMs = pollMs
+    schedulePollLoop()
     poll()
   }
 
@@ -161,7 +174,20 @@ export function startViewing(videoEl, opts = {}) {
   async function poll() {
     if (stopped) return
     try {
-      const { live } = await fetchLiveStatus()
+      const { live, upstreamError } = await fetchLiveStatus()
+      if (upstreamError) {
+        onStatus('无法连接服务器（网关 502/离线），将放慢重试…')
+        const next = Math.min(Math.round(currentPollMs * 1.5), 30000)
+        if (next !== currentPollMs) {
+          currentPollMs = next
+          schedulePollLoop()
+        }
+        return
+      }
+      if (currentPollMs !== pollMs) {
+        currentPollMs = pollMs
+        schedulePollLoop()
+      }
       if (live) {
         if (pollTimer) {
           clearInterval(pollTimer)
@@ -178,8 +204,9 @@ export function startViewing(videoEl, opts = {}) {
     }
   }
 
+  currentPollMs = pollMs
   poll()
-  pollTimer = setInterval(poll, pollMs)
+  schedulePollLoop()
 
   function stop() {
     stopped = true