how to debug description =ERROR - Unable to extract content. Internal error (pdf text extract)

using custom read / connect timeouts but get the following pdf extract error - how do I debug? File is 20mb PDF.

-----error------

python3.10/site-packages/adobe/pdfservices/operation/internal/api/platform_api.py", line 64, in is_correct_response

    raise ServiceApiException(job_error_response.get('message'), ResponseUtil.

adobe.pdfservices.operation.exception.exceptions.ServiceApiException: description =ERROR - Unable to extract content. Internal error; requestTrackingId=d25c9ba3-1b4f-4863-9c81-8fd33d9b019f; statusCode=500; errorCode=ERROR