diff --git a/monitor_android.go b/monitor_android.go
index 2d6f183..735dab9 100644
--- a/monitor_android.go
+++ b/monitor_android.go
@@ -2,6 +2,7 @@ package tun
 
 import (
 	"github.com/sagernet/netlink"
+	E "github.com/sagernet/sing/common/exceptions"
 )
 
 func (m *defaultInterfaceMonitor) checkUpdate() error {
@@ -18,7 +19,7 @@ func (m *defaultInterfaceMonitor) checkUpdate() error {
 	}
 
 	if defaultTableIndex == 0 {
-		return ErrNoRoute
+		return E.Extend(ErrNoRoute, "no rule 0xFFFF")
 	}
 
 	routes, err := netlink.RouteListFiltered(netlink.FAMILY_ALL, &netlink.Route{Table: defaultTableIndex}, netlink.RT_FILTER_TABLE)
@@ -46,5 +47,5 @@ func (m *defaultInterfaceMonitor) checkUpdate() error {
 		return nil
 	}
 
-	return ErrNoRoute
+	return E.Extend(ErrNoRoute, "no route in default table ", defaultTableIndex)
 }