Tried to return to stock, soft bricked my phone.

I tried a method which made me flash a stock RUU, it came up with certification errors.
os- 2.24.401.8
Relocked
Stock recovery
S-ON
When I connect my phone to my Mac, "/.adb devices" returns a blank, but "/.fastboot devices" works.

What can I do to get my device back to stock?