DIAGNOSIS Normal operation. The internal amplifiers and processors generate significant heat during high-bandwidth tasks. The aluminum chassis acts as a heatsink.
FIX Ensure proper ventilation. Do not place the unit on plush carpet, inside an enclosed cabinet, or on top of other electronics that also generate heat. Place it on a hard, flat surface. Leave at least 2 inches of clearance on all sides.
IF THAT DIDN'T WORK Feel the power adapter. If the adapter is excessively hot, not just warm, it may be faulty. A failing adapter can cause the unit to overwork and overheat. Replace it with the official TP-Link 12V/2A adapter.
HEADS UP Heat is expected, but burning smells, audible sizzling, or plastic deformation are not. In those cases, immediately unplug the unit and contact TP-Link support. Do not continue using it.