diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index b63b5e6..78a069f 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -319,6 +319,7 @@
             ssl, group_id, p, end, &key_exchange_len);
         p += key_exchange_len;
         if (ret != 0) {
+            MBEDTLS_SSL_DEBUG_MSG(1, ("client hello: failed generating xxdh key exchange"));
             return ret;
         }