Remote shutdown for Server 2003

Hi I’m trying to shutdown Server 2003 (a few deferent types) by my Desktop in the office however when I try I get a “Access is denied.”

The command I use is “shutdown /s /m \\computername /t 90”

This is a test for a *.bat file I’m working on so if there’s a blackout for to long the servers will be shutdown, we already have the UPS up and running we just need something to shutdown the others.