SSL handshake error while downloading attachments

Hi all,
I have syncing Purchase Invoice from one setup to another. While syncing invoices i need to sync attachments also. But while downloading attachments getting following error -

File "/home/priya/workspace/erun_is/frappe-bench/apps/withrun_integration/withrun_integration/custom/withrun_sync.py", line 671, in download_file
r = requests.get(url)
File "/home/priya/workspace/erun_is/frappe-bench/env/local/lib/python2.7/site-packages/requests/api.py", line 72, in get
return request('get', url, params=params, **kwargs)
File "/home/priya/workspace/erun_is/frappe-bench/env/local/lib/python2.7/site-packages/requests/api.py", line 58, in request
return session.request(method=method, url=url, **kwargs)
File "/home/priya/workspace/erun_is/frappe-bench/env/local/lib/python2.7/site-packages/requests/sessions.py", line 508, in request
resp = self.send(prep, **send_kwargs)
File "/home/priya/workspace/erun_is/frappe-bench/env/local/lib/python2.7/site-packages/requests/sessions.py", line 618, in send
r = adapter.send(request, **kwargs)
File "/home/priya/workspace/erun_is/frappe-bench/env/local/lib/python2.7/site-packages/requests/adapters.py", line 506, in send
raise SSLError(e, request=request)
SSLError: HTTPSConnectionPool(host='beta-wra.with.run', port=443): Max retries exceeded with url: /private/files/ER_Logo1.jpg (Caused by SSLError(SSLError("bad handshake: Error([('SSL routines', 'tls_process_server_certificate', 'certificate verify failed')],)",),))

Please suggest…