diff --git a/cmd/dashboard/controller/service.go b/cmd/dashboard/controller/service.go
index 2a3022c..a5f8b2e 100644
--- a/cmd/dashboard/controller/service.go
+++ b/cmd/dashboard/controller/service.go
@@ -160,15 +160,13 @@ func listServerWithServices(c *gin.Context) ([]uint64, error) {
 	for _, id := range serverIdsWithService {
 		singleton.ServerLock.RLock()
 		server, ok := singleton.ServerList[id]
-		if !ok {
-			singleton.ServerLock.RUnlock()
+		singleton.ServerLock.RUnlock()
+		if !ok || server == nil {
 			return nil, singleton.Localizer.ErrorT("server not found")
 		}
-
 		if !server.HideForGuest || authorized {
 			ret = append(ret, id)
 		}
-		singleton.ServerLock.RUnlock()
 	}
 
 	return ret, nil
diff --git a/service/rpc/auth.go b/service/rpc/auth.go
index fa601dd..a99949b 100644
--- a/service/rpc/auth.go
+++ b/service/rpc/auth.go
@@ -75,6 +75,7 @@ func (a *authHandler) Check(ctx context.Context) (uint64, error) {
 		singleton.ServerList[s.ID] = &s
 		singleton.ServerUUIDToID[clientUUID] = s.ID
 		singleton.ServerLock.Unlock()
+
 		singleton.ReSortServer()
 
 		clientID = s.ID
diff --git a/service/rpc/nezha.go b/service/rpc/nezha.go
index ba49661..98996fb 100644
--- a/service/rpc/nezha.go
+++ b/service/rpc/nezha.go
@@ -133,17 +133,22 @@ func (s *NezhaHandler) onReportSystemInfo(c context.Context, r *pb.Host) error {
 	singleton.ServerLock.RLock()
 	defer singleton.ServerLock.RUnlock()
 
+	server, ok := singleton.ServerList[clientID]
+	if !ok || server == nil {
+		return fmt.Errorf("server not found")
+	}
+
 	/**
 	 * 这里的 singleton 中的数据都是关机前的旧数据
 	 * 当 agent 重启时，bootTime 变大，agent 端会先上报 host 信息，然后上报 state 信息
 	 * 这是可以借助上报顺序的空档，将停机前的流量统计数据标记下来，加到下一个小时的数据点上
 	 */
-	if singleton.ServerList[clientID].Host != nil && singleton.ServerList[clientID].Host.BootTime < host.BootTime {
-		singleton.ServerList[clientID].PrevTransferInSnapshot = singleton.ServerList[clientID].PrevTransferInSnapshot - int64(singleton.ServerList[clientID].State.NetInTransfer)
-		singleton.ServerList[clientID].PrevTransferOutSnapshot = singleton.ServerList[clientID].PrevTransferOutSnapshot - int64(singleton.ServerList[clientID].State.NetOutTransfer)
+	if server.Host != nil && server.Host.BootTime < host.BootTime {
+		server.PrevTransferInSnapshot = server.PrevTransferInSnapshot - int64(server.State.NetInTransfer)
+		server.PrevTransferOutSnapshot = server.PrevTransferOutSnapshot - int64(server.State.NetOutTransfer)
 	}
 
-	singleton.ServerList[clientID].Host = &host
+	server.Host = &host
 	return nil
 }