InvalidBusinessParameterError Encountered without Further Explanation

[BenediktPrusas]

Issue Description:
I'm experiencing an InvalidBusinessParameterError when trying to query cross-border flows using the query_crossborder_flows method. The error message doesn't provide any further details, making it difficult to understand what's going wrong. I am useing the version 0.5.10.

Code to reproduce the error:

from entsoe import EntsoePandasClient

client = EntsoePandasClient(api_key=<YOUR API KEY HERE>)
start = pd.to_datetime('2020-01-01').tz_localize('UTC')
end = pd.to_datetime('2020-01-02').tz_localize('UTC')
client.query_crossborder_flows("IT_CNOR","IT_SARD", start=start, end=end)

[fboerman]

hi did you check this data is available in the UI?