How do I remove my KitchenAid attachment?
It is usually stuck because of fresh or old food particles getting into the socket or release mechanism

The simplest way is to drizzle boiling water onto the release mechanism. A few large pours over some minutes may be required to soften and remove the food particles

A quick spray of silicone oil may be required after this as the boiling water removes all factory lubrication too

Unplug the machine first! and take great care not to get water into the motor or electronic parts. Position the device over a sink or bucket so that water will flow away from the motor and electronic parts