ITSM: Service State - how to change state of service

[melon23]

Hi
I want to know how OTRS:ITSM calculate Service state one page:
https://server.test/otrs/index.pl?Actio ... TSMService

On this page you can see a list od services and colour indicators showing the service state
Normaly colour of indicators is green - Production State

But when it became Red or Yelow ?
What should hapen to achieve this ?

I tested it in many variants but always services are Green (Production)

Thanks in advance
Melon23