diff --git a/src/authserver/Server/AuthSocket.cpp b/src/authserver/Server/AuthSocket.cpp
index b9e935a6d..b9671c0d1 100644
--- a/src/authserver/Server/AuthSocket.cpp
+++ b/src/authserver/Server/AuthSocket.cpp
@@ -557,7 +557,7 @@ bool AuthSocket::_HandleLogonProof()
     A.SetBinary(lp.A, 32);
 
     // SRP safeguard: abort if A == 0
-    if (A.isZero())
+    if ((A % N).isZero())
     {
         socket().shutdown();
         return true;