diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 7187533..0a31d79 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -78,7 +78,7 @@
 #define MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED                 -0x7680  /**< No CA Chain is set, but required to operate. */
 #define MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE                -0x7700  /**< An unexpected message was received from our peer. */
 #define MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE               -0x7780  /**< A fatal alert message was received from our peer. */
-/* NOTE: Error space gap */
+#define MBEDTLS_ERR_SSL_UNRECOGNIZED_NAME                 -0x7800  /**< No server could be identified matching the client's SNI. */
 #define MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY                 -0x7880  /**< The peer notified us that the connection is going to be closed. */
 #define MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO               -0x7900  /**< Processing of the ClientHello handshake message failed. */
 #define MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO               -0x7980  /**< Processing of the ServerHello handshake message failed. */