Hi. Anyone here who could help me setup a Rust server? I've got an error that my server host cannot resolve. 

Fresh server, 3500 map size, default Oxide installation, no players, using maximum RAM and causing crash.

The server provider says plugins are the likely cause however I've only installed the basic ones such as Gather Manager etc. I've not even setup permissions yet and the server cannot cope. 

I'm not sure whether I've done something wrong in Commandline, etc. But that's obviously not right. 

Server has 6GB RAM.

3500 with plugins and less than 10 pop will use 6-10GB of RAM.

Upgrade, through your server provider, your memory, or get a better server host. Streamline & swiftnode are good.
Restarts will immediately reduce memory usage. Maybe set some bi-daily auto-restarts with warnings.