diff --git a/td/mtproto/Transport.cpp b/td/mtproto/Transport.cpp
index 4454fefb4..1a98182dd 100644
--- a/td/mtproto/Transport.cpp
+++ b/td/mtproto/Transport.cpp
@@ -416,7 +416,7 @@ Result<uint64> Transport::read_auth_key_id(Slice message) {
 }
 
 Result<Transport::ReadResult> Transport::read(MutableSlice message, const AuthKey &auth_key, PacketInfo *packet_info) {
-  if (message.size() < 12) {
+  if (message.size() < 16) {
     if (message.size() < 4) {
       return Status::Error(PSLICE() << "Invalid MTProto message: smaller than 4 bytes [size = " << message.size()
                                     << "]");