In ITIL, SLAs apply to services or other objects. It doesn't make sense to open a ticket against just a SLA object; it's a set of rules describing evaluation parameters, not a failing object itself. Think of it as a Boolean value. You have to identify what the combination of rule and object the rule applies to in order to have something that can be treated as a failure; rule sets can't fail on their own, they only fail in context with another object. From: dev-bounces@otrs.org [mailto:dev-bounces@otrs.org] On Behalf Of Jignesh Kakka (jkakka) Sent: Friday, February 22, 2013 4:38 PM To: dev@otrs.org Subject: [dev] Why is Service Mandatory while creating ticket against for SLA? I am trying to create ticket against SLA. It complains that SLA is invalid field <ErrorCode>TicketCreate.InvalidParameter</ErrorCode> <ErrorMessage>TicketCreate: Ticket->SLAID or Ticket->SLA parameter is invalid!</ErrorMessage> Now when I ran this code after adding service, it created ticket Thanks, Jignesh