If your Optigrill goes to manual settings only, it probably means that you have placed the meat inside the grill before allowing the device to perform pre heat. If that is the case, remove the food from the grill, close the lid, and shut down the machine. Powering on the device now should allow you to select one of the preset items.
If you still cannot select a preset, power off the machine and check that the grill plates are correctly placed and that nothing is preventing them from closing up entirely.
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