Your entitlement may be subject to a mandatory corporate action, where the confirmation of the entitlement has not yet been received by the pay date. In such cases, Cornèrtrader blocks the security from being traded until the confirmation from the counterparty is received.
Once the confirmation is sent and the entitlement is made available for trading (in the case of tradable instalments), the entitlements will be booked to your account and can be traded.