Hi @AntonyThanislas -
"Response not yet ready" means your activation is still running, so you should wait a bit more to get the response.
"There was an error processing your request" means your activation finished with an error. You could check the activation record and logs to see what went wrong.
Please note that the default timeout of activations is 1 min. You mentioned that the action is time consuming, so for non-blocking activations (e.g. invoked by CLI, not web requests), you can increase the timeout up to 30 min.