The problem may be resolved by performing a factory reset on your system as the the factory reset re-calibrates a number of low level controllers including CD controllers (as well as resetting the product’s operating system), often resolving issues like this.

Start by making sure the aerial is fully extended and/or vertical, and perform the factory reset as described in the product user guide under the 'Hints And Tips' section. A factory reset is normally performed by pressing and holding the ‘Menu’ or ‘Setup’ button down for two or three seconds and then following the on-screen instructions.

If the factory reset does not regain control of the CD tray it may have suffered a mechanical malfunction and you should contact your retailer for the best course of action to take.