In the Investment screen, select the Bond and check the purchase value for the Bond. If this box is blank or shows £0, this will be the cause of the issue. If it is an existing Bond, make sure you enter the purchase value. For new Bonds, check how the Bond has been set up. At present, if you try to purchase a new Bond via a transfer rather than by adding a purchase value it effectively creates a Bond without a cost basis. The software cannot calculate the taxation and therefore disallows all future withdrawals.
This is on the radar for our development team to fix, however, in the meantime, to get withdrawals from the Bond, you will need to enter a purchase value for the Bond. Details of how to set up a new Bond this way can be found in the article in the link here.
Once there is an initial purchase value for the Bond, withdrawals will be allowed. Click here to find out more about how to set up planned withdrawals from a Bond.