On some CPUs, XMRig tries to increase performance by disabling certain features like your CPU's instruction prefetcher. These operations require root/administrator, so try right clicking xmrig.exe and running it as administrator, or running `sudo ./xmrig` on other systems.
Find the line in config.json that says `algo: null` and change it to `algo: "rx/0"`. By default, XMRig expects the pool to tell it which hashing algorithm to use.
Taken from [the MSDN](https://docs.microsoft.com/en-us/sql/database-engine/configure-windows/enable-the-lock-pages-in-memory-option-windows?view=sql-server-ver15):