Based on your license, you have a certain number of tokens that you can use to create Remote Engine Gen2s, Remote Engines, or allocate Cloud Engines to environments.
Executing a task or a plan on a shared (unassigned) Cloud Engine also consumes engine tokens. Once all the tokens are used up, it is not possible to create new engines or assign Cloud Engines.
The number of Cloud Engines marked as In Use is the sum of the running and allocated Cloud Engines. Cloud Engine for Design is not counted as a Cloud Engine, and it does not consume tokens.
To purchase new tokens, contact your customer success manager or email email@example.com.