Diagnosis
Complete power failure. The thermal fuse on the control board has likely blown, or there is an internal break in the power cord.
How to Fix It
Check the power cord first. Trace its entire length for kinks, cuts, or damage near the plug or where it enters the base. Try a different, known-good outlet. Ensure the outlet is providing power.
If That Didn't Work
The issue is internal. The primary suspect is the thermal fuse on the main control board. This is a safety device that trips if the motor overheats. Replacing it requires disassembling the base and soldering. This is not a user repair.
Heads Up
Do not disassemble the base. The capacitor inside can hold a dangerous charge even when unplugged. Contact Ninja support. A dead base with no signs of life is typically a warranty or replacement scenario.