> Maybe setting it to "1" is not supported, and raises an error. Indeed. lib/url.c: failf(data, "CURLOPT_SSL_VERIFYHOST no longer supports 1 as value!"); You didn't see the message due to another bug in pycurl. The reset() method throws away the error buffer and urlgrabber used to call it. You need to upgrade urlgrabber or downgrade libcurl.