I developed a flow action to call Robot Automation from Pega Platform. I cannot run the automation. However, after I accessed the URL (https://localruntime.pega.com:9443/api/v1/runtime/IsAvailable), the automation is able to run initiated from Pega. I haven't changed anything except access the URL. Do we need to access this URL every time that we start the Robot? Why we need to run this automation first?
The only reason I can think of that your automation worked correctly after you hit the endpoint is because Robotic Runtime was still starting up its rest services to listen for traffic from pega platform when you called the automation for first time.
Perform following test:
Start Robotics Runtime and wait a minute
Call the automation from Pega Platform
If the issue still occurs after the test, you need to open a support request for further investigation.