You may be attempting to connect to Pretendo through the SSSL method on a console version of 5.5.4 or older. This will not work, as SSSL requires the console to be on at least version 5.5.5. You must unblock updates if they are blocked, and then update the console.
If you are already on 5.5.5+, or are using Inkay, then something on your network may be interfering with Pretendo.
For further support with this error code or any associated error codes, please look for a solution or make a support post on the forum.