My data lake and data analyzer are in the same subnet. Why doesn't the data lake receive logs?

Despite your Stellar Cyber hosts residing in the same subnet, it's not guaranteed that they can pass data between themselves. There might be security restrictions in the firewall of each host. Regardless of how you've configured your network overall, inspect routing between hosts at a non-typical port, like 8889 for example. It's best practice to have an exclusive route between your hosts with all ports open bi-directionally and with higher priority than general traffic.