diff --git a/src/java/davmail/http/DavGatewayHttpClientFacade.java b/src/java/davmail/http/DavGatewayHttpClientFacade.java
index 8f378cad..d3cf8653 100644
--- a/src/java/davmail/http/DavGatewayHttpClientFacade.java
+++ b/src/java/davmail/http/DavGatewayHttpClientFacade.java
@@ -418,6 +418,8 @@ public final class DavGatewayHttpClientFacade {
      * @param httpClient HttpClient instance
      */
     public static void addNTLM(HttpClient httpClient) {
+        // disable preemptive authentication
+        httpClient.getParams().setParameter(HttpClientParams.PREEMPTIVE_AUTHENTICATION, false);
         // NTLM authentication uses persistent connections, use private connection manager
         httpClient.setHttpConnectionManager(createConnectionManager());
         // register the jcifs based NTLMv2 implementation