FAIL_PROTO
smtp_client_abort(proto, FAIL_PROTO, "Line too long");
smtp_client_abort(proto, FAIL_PROTO, "Response too short");
smtp_client_abort(proto, FAIL_PROTO, "Invalid reply code");
smtp_client_abort(proto, FAIL_PROTO,
smtp_client_abort(proto, FAIL_PROTO, "Trailing data");
case FAIL_PROTO: