When i boot up my Rust Server it crashes with the error " Please specify a startup command. "  and i don't know why because i have a startup command
Please can somebody help me?

Could you provide a screenshot and log please?

yeah, sure

here

I'm not sure what you are using, so I'd suggest contacting the host or developer of the project you are using to install. I'd also suggest clarifying with them that you are installing Oxide, as uMod is not released and shouldn't be used on a live server.

hello, i've deactivated uMod and still the same problem.

Gamer2000

hello, i've deactivated uMod and still the same problem.

I wasn't suggesting that your installation of Oxide or uMod was the issue, it's the tool you are using.