[SalesForce] Omnichannel skill based routing, not assigning case to service agent

I followed all the steps mentioned here to setup skill based routing

• Enable Omni-Channel
• Enable Skills-Based Routing Enable skill-based routing in your org.
• Create Skills for Skills-Based Routing Skills identify your agents’ areas of
  expertise.
• Create Service Resources for Agents Service resources
  represent individual agents. Create a service resource for each
  agent.
• Assign Skills to Service Resources Assign skills to your
  agents to track their areas of experience and their level of
  proficiency for each skill.
• Route Work Items
  Using Skills To route non-Chat work items using skills, create a
  PendingServiceRouting object and the associated SkillRequirement
  objects. The PendingServiceRouting object is a standard Salesforce
  object that represents the work item that is going to be routed. The
  SkillRequirement object is a standard Salesforce object that
  represents the skill and the proficiency level.

My apex class works fine to assign skills to work item but still the case is not routed to an agent.

I am new to salesforce. There is no point mentioned to route a case to agent so I was expecting omnichannel to handle it but it does not seem to work.
I have added permission set to add statuses to service agent for them to be online to receive a case.
I tested with a service agent online but unable to route the case.

Please let me know if I am missing a step here or something i need to configure.
Any help is appreciated.

Thanks
Khyati