Unknown error in downloading 'reanalysis-era5-complete'

I'm trying a simple test retrieve of ERA5 data using  sample script in How to download ERA5.

When I download 'reanalysis-era5-pressure-levels' everything is fine, but
error in downloading 'reanalysis-era5-complete'. 

I get the following error message.

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2023-05-25 15:32:45,013 INFO Welcome to the CDS
2023-05-25 15:32:45,015 INFO Sending request to https://cds.climate.copernicus.eu/api/v2/resources/reanalysis-era5-complete
2023-05-25 15:32:45,342 INFO Request is queued
2023-05-25 15:32:46,600 INFO Request is failed
2023-05-25 15:32:46,601 ERROR Message: an internal error occurred processing your request
2023-05-25 15:32:46,601 ERROR Reason:  You should set "$schema" or "_draft" in your schema
2023-05-25 15:32:46,602 ERROR   Traceback (most recent call last):
2023-05-25 15:32:46,602 ERROR     File "/opt/cdstoolbox/cdscompute/cdscompute/cdshandlers/services/handler.py", line 59, in handle_request
2023-05-25 15:32:46,603 ERROR       result = cached(context.method, proc, context, context.args, context.kwargs)
2023-05-25 15:32:46,603 ERROR     File "/opt/cdstoolbox/cdscompute/cdscompute/caching.py", line 108, in cached
2023-05-25 15:32:46,604 ERROR       result = proc(context, *context.args, **context.kwargs)
2023-05-25 15:32:46,604 ERROR     File "/opt/cdstoolbox/cdscompute/cdscompute/services.py", line 124, in __call__
2023-05-25 15:32:46,605 ERROR       return p(*args, **kwargs)
2023-05-25 15:32:46,605 ERROR     File "/opt/cdstoolbox/cdscompute/cdscompute/services.py", line 60, in __call__
2023-05-25 15:32:46,606 ERROR       return self.proc(context, *args, **kwargs)
2023-05-25 15:32:46,606 ERROR     File "/home/cds/cdsservices/services/mars/mars.py", line 53, in external
2023-05-25 15:32:46,607 ERROR       return mars(context, request, **kwargs)
2023-05-25 15:32:46,607 ERROR     File "/home/cds/cdsservices/services/mars/mars.py", line 18, in mars
2023-05-25 15:32:46,608 ERROR       **kwargs)
2023-05-25 15:32:46,609 ERROR     File "/home/cds/cdsservices/services/mars/preprocess_request.py", line 22, in preprocess_request
2023-05-25 15:32:46,609 ERROR       requests = enforce_dataset_schema(requests, context)
2023-05-25 15:32:46,610 ERROR     File "/opt/cdstoolbox/cds-common/cds_common/request_schemas/enforce_schema.py", line 51, in enforce_dataset_schema
2023-05-25 15:32:46,610 ERROR       request = enforce_schema(request, schema, context)
2023-05-25 15:32:46,611 ERROR     File "/opt/cdstoolbox/cds-common/cds_common/request_schemas/enforce_schema.py", line 21, in enforce_schema
2023-05-25 15:32:46,611 ERROR       request = enforce(request, schema, mapping=mapping, logger=context)
2023-05-25 15:32:46,612 ERROR     File "/opt/cdstoolbox/cds-common/cds_common/request_schemas/enforce.py", line 35, in enforce
2023-05-25 15:32:46,612 ERROR       validator = get_validator(schema)
2023-05-25 15:32:46,613 ERROR     File "/opt/cdstoolbox/cds-common/cds_common/request_schemas/get_validator.py", line 89, in get_validator
2023-05-25 15:32:46,613 ERROR       raise Exception('You should set "$schema" or "_draft" in your '
2023-05-25 15:32:46,614 ERROR   Exception: You should set "$schema" or "_draft" in your schema

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Can someone explain what is happening in this case? Looking forward to any reply!