Are you doing a PhD?
If so, Please contact the OU for a voucher code to apply.
Are you actively studying a module?
If you are waiting to start a module or you are inbetween modules your PI number will not be accepted until you have actively started studying your module.
Do all the details you are entering match up to the details the OU have for you?
All the details you have provided us with will need to match up EXACTLY to the ones the Open University have for yourself otherwise the application will not be accepted.