Problem opening connection to SQL Server DB using pyodbc and machine learning services

I have Anaconda installed on one of our servers, and some code which successfully opens a connection to SQL (2016) on another server:

import pyodbc

conn_string = 'DRIVER={SQL Server Native Client 11.0};SERVER=wpic-smir;Trusted_Connection=yes'
conn = pyodbc.connect(conn_string)
cursor=conn.cursor()

qstring = 'select UserID from Diler_BW.Beckwith.V_Thermovals'
cursor.execute(qstring)

row=cursor.fetchone()
print row[0]

del cursor
del conn

Now, on the same server as Anaconda, we have SQL Server (2017) installed, and Machine Learning Service for Python is also installed. I'm trying to do run essentially the same code above, but from within SQL:

exec sp_execute_external_script
@LANGUAGE = N'Python',
@script = N'

import pyodbc

conn_string = ''DRIVER={SQL Server Native Client 11.0};SERVER=wpic-smir;Trusted_Connection=yes''
conn = pyodbc.connect(conn_string)
cursor=conn.cursor()

qstring = ''select UserID from Diler_BW.Beckwith.V_Thermovals''
cursor.execute(qstring)

row=cursor.fetchone()
print row[0]

del cursor
del conn
'

The code runs successfully from standalone Anaconda, but, from a SQL query connected to the 2017 server, it does not:

Msg 39004, Level 16, State 20, Line 0
A 'Python' script error occurred during execution of 'sp_execute_external_script' with HRESULT 0x80004004.
Msg 39019, Level 16, State 2, Line 0
An external script error occurred: 

Error in execution.  Check the output for more information.
Traceback (most recent call last):
  File "<string>", line 5, in <module>
  File "C:\ProgramData\MSSQLSERVER\Temp-PY\Appcontainer1\41EF254D-1B14-4D9D-99AF-8AD356A84BDC\sqlindb_0.py", line 39, in transform
    conn = pyodbc.connect(conn_string)
pyodbc.OperationalError: ('08001', '[08001] [Microsoft][SQL Server Native Client 11.0]Named Pipes Provider: Could not open a connection to SQL Server [65].  (65) (SQLDriverConnect); [08001] [Microsoft][SQL Server Native Client 11.0]Login timeout expired (0); [08001] [Microsoft][SQL Server Native Client 11.0]A network-related or instance-specific error has occurred while establishing a connection to SQL Server. Server is not found or not accessible. Check if instance name is correct and if SQL Server is configured to allow remote connections. For more information see SQL Server Books Online. (65)')


Msg 39019, Level 16, State 2, Line 0
An external script error occurred: 
SqlSatelliteCall error: Error in execution.  Check the output for more information.
STDOUT message(s) from external script: 

Express Edition will continue to be enforced.
SqlSatelliteCall function failed. Please see the console output for more information.
Traceback (most recent call last):
  File "C:\Program Files\Microsoft SQL Server\MSSQL15.MSSQLSERVER\PYTHON_SERVICES\lib\site-packages\revoscalepy\computecontext\RxInSqlServer.py", line 605, in rx_sql_satellite_call
    rx_native_call("SqlSatelliteCall", params)
  File "C:\Program Files\Microsoft SQL Server\MSSQL15.MSSQLSERVER\PYTHON_SERVICES\lib\site-packages\revoscalepy\RxSerializable.py", line 375, in rx_native_call
    ret = px_call(functionname, params)
RuntimeError: revoscalepy function failed.

The account I'm using for development is in the sysadmin role on both servers. We use Windows authentication only on both servers. I assume that something significant is different about the instance of python that SQL/MLS uses than the standalone installation.

Thank you.