The printhead lift motor stalled. The lift motor did not find a reference point to stop at while lowering.

Turn power off and then on.

Check for a damaged cable and connectors while reseating the FFC between the printhead assembly and the main PCA (J13). If damage is found, replace the printhead assembly FFC cable kit
(J25) is a ZIF (zero insertion force) FFC. Unlatch the connector by carefully rotating the tab away from the PCA, pulling it from the top. There are two small tabs at each side of the cable that keep the connector aligned.