diff --git a/all/ipv6.txt b/all/ipv6.txt
index 7b9790bd..ff48e9f5 100644
--- a/all/ipv6.txt
+++ b/all/ipv6.txt
@@ -2760,7 +2760,7 @@
 2404:f340::/32
 2405:8100::/32
 2405:b500::/32
-2406:da00:800::/64
+2406:da00:800::/40
 2406:da00:1000::/40
 2406:da00:2000::/40
 2406:da00:4000::/40
diff --git a/all/ipv6_merged.txt b/all/ipv6_merged.txt
index 1a8c01c9..e7835a2b 100644
--- a/all/ipv6_merged.txt
+++ b/all/ipv6_merged.txt
@@ -436,7 +436,7 @@
 2404:f340::/32
 2405:8100::/32
 2405:b500::/32
-2406:da00:800::/64
+2406:da00:800::/40
 2406:da00:1000::/40
 2406:da00:2000::/40
 2406:da00:4000::/40
diff --git a/amazon/ipv6.txt b/amazon/ipv6.txt
index 7c659fa1..21b60b06 100644
--- a/amazon/ipv6.txt
+++ b/amazon/ipv6.txt
@@ -322,7 +322,7 @@
 2404:c2c0:8000::/36
 2404:c2c0:c000::/36
 2404:c2c0::/40
-2406:da00:800::/64
+2406:da00:800::/40
 2406:da00:1000::/40
 2406:da00:2000::/40
 2406:da00:4000::/40
diff --git a/amazon/ipv6_merged.txt b/amazon/ipv6_merged.txt
index 19de02f0..ee668bef 100644
--- a/amazon/ipv6_merged.txt
+++ b/amazon/ipv6_merged.txt
@@ -250,7 +250,7 @@
 2404:c2c0:8000::/36
 2404:c2c0:c000::/36
 2404:c2c0::/40
-2406:da00:800::/64
+2406:da00:800::/40
 2406:da00:1000::/40
 2406:da00:2000::/40
 2406:da00:4000::/40