diff --git a/source3/libsmb/cliconnect.c b/source3/libsmb/cliconnect.c
index 63c505f8ed5..d894ef76a36 100644
--- a/source3/libsmb/cliconnect.c
+++ b/source3/libsmb/cliconnect.c
@@ -1450,6 +1450,8 @@ struct tevent_req *cli_session_setup_creds_send(TALLOC_CTX *mem_ctx,
 	uint32_t in_sess_key = 0;
 	const char *in_native_os = NULL;
 	const char *in_native_lm = NULL;
+	enum credentials_use_kerberos krb5_state =
+		cli_credentials_get_kerberos_state(creds);
 	NTSTATUS status;
 
 	req = tevent_req_create(mem_ctx, &state,
@@ -1491,6 +1493,13 @@ struct tevent_req *cli_session_setup_creds_send(TALLOC_CTX *mem_ctx,
 		return req;
 	}
 
+	if (krb5_state == CRED_USE_KERBEROS_REQUIRED) {
+		DBG_WARNING("Kerberos authentication requested, but "
+			    "the server does not support SPNEGO authentication\n");
+		tevent_req_nterror(req, NT_STATUS_NETWORK_CREDENTIAL_CONFLICT);
+		return tevent_req_post(req, ev);
+	}
+
 	if (smbXcli_conn_protocol(cli->conn) < PROTOCOL_LANMAN1) {
 		/*
 		 * SessionSetupAndX was introduced by LANMAN 1.0. So we skip