If your vehicle is showing trunk or liftgate won't open with button or key, here are the most likely causes and the parts you'll need to fix each one.
The electronic motor or latch mechanism that releases the trunk has burned out, stripped its internal gears, or broken. This prevents both the button and the fob from unlatching the trunk.
The battery inside your key fob has died, preventing the remote signal from reaching the car. If the interior button also doesn't work, this may be combined with a valet mode issue.
A security switch inside the glove box or center console was accidentally flipped, intentionally disabling the electronic trunk release. This frequently happens by mistake after replacing a cabin air filter or detailing the interior.
Repeated opening and closing of the trunk can fatigue and snap the wires inside the rubber boot at the hinge, cutting power to the latch actuator and sometimes blowing a fuse.
If the main vehicle battery is completely dead or disconnected, the electronic trunk release will not have the power required to operate.
If you rely on the electronic button and rarely use the physical key, the mechanical lock cylinder can corrode and seize over time, preventing manual entry when the electronics fail.
The main computer that controls body electronics has failed or requires a reset, preventing the trunk release signal from being processed.