Unable to use Adobe PDF Services API

I'm trying to extract PDF data to json.
I'm using Adobe PDF Services API which is included in Free trial.

I successfully generated client id and client secret. But when I'm trying to extract using SDK I got the error 'throw new ServiceUsageError_1.ServiceUsageError(errorMessage, requestId, responseStatus, errorCode);
^
ServiceUsageError: Either Quota for this operation is not available or Free trial quota is exhausted
'

And also, when I'm trying to create project for credential I got error as 'API configuration failed for service DocCloudSDK with code 500 from ATLS. Please try again.'  but I was able to successfuly generate credentials.

How can I resolve this issue.
PS. I'm using this service for the first time.