Getting data from XML API fails in copy data but works in web activity

Here is what I did to test that I could get it to work. 

from io import StringIO # https://docs.python.org/3/library/io.html#io.StringIO
import pandas as pd # https://pandas.pydata.org/docs/reference/index.html
import requests # https://requests.readthedocs.io/en/latest/

# Setup Request Variables.

base_url = 'https://vsac.nlm.nih.gov/vsac/svs/'
end_point = 'RetrieveMultipleValueSets'
parameters = {'id':'2.16.840.1.113883.3.117.1.7.1.226','release':'eCQM Update 2020-05-07'}

# Request - Basic Authentication values have been removed 

response = requests.get(f"{base_url}{end_point}",params=parameters,auth=('userName','password'))

# Warns about using response.text directly using StringIO as suggested 
xml_io_concept = StringIO(response.text)

# Define namespaces
namespaces = {
    'ns0': 'urn:ihe:iti:svs:2008',
    'xsi': 'http://www.w3.org/2001/XMLSchema-instance'
}

# Parse the XML and extract Concept elements
pandas_df = pd.read_xml( # https://pandas.pydata.org/docs/reference/api/pandas.read_xml.html
    xml_io_concept,
    xpath=".//ns0:Concept",
    namespaces=namespaces
)

# Convert Pandas to PySpark 

spark_df = spark.createDataFrame(pandas_df)

# Write to table in default Lakehouse 

spark_df.write.format("delta").mode("overwrite").option("overwriteSchema", "true").save(f"Tables/test_value_set")

# Query Lakehouse Table

df = spark.sql("SELECT * FROM ValueSet_Lake.test_value_set LIMIT 1000")
display(df)