It's a known issue, waiting for Valve to release a fix for A2S queries. Meanwhile you can install [Metamod](https://www.sourcemm.net/downloads.php?branch=dev) and [this plugin](https://github.com/Source2ZE/ServerListPlayersFix).
It's a known issue, waiting for Valve to release a fix for A2S queries.
Meanwhile you can install Metamod and this plugin.