diff --git a/td/telegram/net/ConnectionCreator.cpp b/td/telegram/net/ConnectionCreator.cpp
index 3db71f0e..bd65535c 100644
--- a/td/telegram/net/ConnectionCreator.cpp
+++ b/td/telegram/net/ConnectionCreator.cpp
@@ -1199,6 +1199,7 @@ void ConnectionCreator::start_up() {
       proxy_last_used_date_[proxy_id] = last_used;
       proxy_last_used_saved_date_[proxy_id] = last_used;
     } else {
+      CHECK(!ends_with(info.first, "_max_id")) << info.first;
       int32 proxy_id = info.first == "proxy" ? 1 : to_integer_safe<int32>(Slice(info.first).substr(5)).move_as_ok();
       CHECK(proxies_.count(proxy_id) == 0);
       log_event_parse(proxies_[proxy_id], info.second).ensure();