This error indicates that you are accessing Betfair from a location that is restricted for legal or regulatory reasons. You will need to access Betfair from a different location. You can use https://www.maxmind.com/en/geoip-demo to identify the specific location to which your IP address has been assigned by your service provider.
If your IP is (incorrectly) identified as being based in the US (or any other restricted location) you will need to submit a correction request to Maxmind via https://www.maxmind.com/en/correction
One confirmed by Maxmind, any corrections will be applied when we upload the latest GeoIP files to our servers on a Thursday evening, as part of a weekly process.
Unfortunately, we cannot apply manual whitelisting and need to wait for Maxmind to apply the change as they are the source of truth for all of our GeoIP info.