No power to fuse box
 

Hey yall,
I have a 1996 Miata that won’t start and has no power to any of the electronics. After shutting off the car I heard a popping noise and then all the electronics shut off. Battery is good and measured 12.9 volts. The main fuse is also good but there’s no power at the fuse box. Would appreciate suggestions for diagnosing this issue.
Thanks