diff --git a/adapter/outbound/util.go b/adapter/outbound/util.go
index 0b859630..d5219131 100644
--- a/adapter/outbound/util.go
+++ b/adapter/outbound/util.go
@@ -104,7 +104,7 @@ func resolveUDPAddrWithPrefer(network, address string, prefer C.DNSPrefer) (*net
 			ip = fallback
 		}
 	default:
-		// C.IPv4Prefer, C.DualStack and other 
+		// C.IPv4Prefer, C.DualStack and other
 		var ips []netip.Addr
 		ips, err = resolver.ResolveAllIPProxyServerHost(host)
 		var fallback netip.Addr
@@ -119,7 +119,10 @@ func resolveUDPAddrWithPrefer(network, address string, prefer C.DNSPrefer) (*net
 					}
 				}
 			}
-			ip = fallback
+
+			if !ip.IsValid() && fallback.IsValid() {
+				ip = fallback
+			}
 		}
 	}