When a flow action is part of the authentication policy, the flow drops off specific context data that cannot be passed through the browser as query or form parameters due to security constraints. The flow execution context endpoint captures these input and output paramaters and returns a contextUri to the flow execution service, which is included in the experience URL. For example:

https://auth.pingone.com/{envId}/experiences/{flowNameOrID}?redirectUri=https://auth.pingone.com/{envId}/flows/{flowId}/flowExecutionCallback?contextUri={contextUri}