[Python] Trouble clearing cache in python

I have python code that uses astroquery that has been working for 2 years, but now gives an error code (copied below) suggesting the SSL certificate for NASA Horizons is out of date. I wrote to those who administer the NASA Horizons database who said that an old certificate is stuck somewhere in my cache. I can't find where that is, and I have the same problem on two machines I have run the code on, one is a Mac the other a Windows system. I can't find any cache files on either one that relate to Horizons, astroquery, or python files. Can anyone suggest locations to look?

JPLHorizons instance "299"; location=662, epochs=[{'2025-02-06 01:47:13'}], id_type=None
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/urllib3/connectionpool.py", line 603, in urlopen
chunked=chunked)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/urllib3/connectionpool.py", line 344, in _make_request
self._validate_conn(conn)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/urllib3/connectionpool.py", line 843, in _validate_conn
conn.connect()
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/urllib3/connection.py", line 370, in connect
ssl_context=context)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/urllib3/util/ssl_.py", line 355, in ssl_wrap_socket
return context.wrap_socket(sock, server_hostname=server_hostname)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/ssl.py", line 412, in wrap_socket
session=session
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/ssl.py", line 853, in _create
self.do_handshake()
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/ssl.py", line 1117, in do_handshake
self._sslobj.do_handshake()
ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: self signed certificate in certificate chain (_ssl.c:1056)

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