diff --git a/ipv6/mx.cidr b/ipv6/mx.cidr
index 049dadcac..4a6255adf 100644
--- a/ipv6/mx.cidr
+++ b/ipv6/mx.cidr
@@ -115,5 +115,5 @@
 2806:3c0::/27
 2806:3e0::/28
 2806:3f0::/29
-2806:3f9::/32
+2806:3f8::/31
 2806:1000::/24