I've just checked cert login and it's working fine for me. I'm using a UK-based IP address, and https://identitysso.betfair.com/api/certlogin/ as the end-point. This url has always returned that 'oops' error in a browser for an HTTP GET request, but works ok for POST requests.
Just a thought prompted by the error message, but is it possible that it's the path to your local copy of the cert / key files that is the problem?
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