Ignoring certificate errors with NSURLConnection

I am getting this error

The certificate for this server is invalid. You might be connecting to a server
that is pretending to be "server addres goes here" which could put your
confidential information at risk."

I am using this method:

[NSURLConnection sendSynchronousRequest:request
                      returningResponse:&response
                                  error:&error];

How can I fix this?

I tried this code:

 NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request
                                                               delegate:self];

but then I get EXC_BAD_ACCESS in the didReceiveResponse method.