Error opening HID Manager

Describe the Bug

*** QMK Toolbox (http://qmk.fm/toolbox)
    Supporting following bootloaders:
     - DFU (Atmel, LUFA) via dfu-programmer (http://dfu-programmer.github.io/)
     - Caterina (Arduino, Pro Micro) via avrdude (http://nongnu.org/avrdude/)
     - Halfkay (Teensy, Ergodox EZ) via teensy_loader_cli (https://pjrc.com/teensy/loader_cli.html)
     - STM32 (ARM) via dfu-util (http://dfu-util.sourceforge.net/)
     - Kiibohd (ARM) via dfu-util (http://dfu-util.sourceforge.net/)
    And the following ISP flasher protocols:
     - USBTiny (AVR Pocket)
     - AVRISP (Arduino ISP)
*** Halfkay device connected
*** Attempting to flash, please don't remove device
>>> teensy_loader_cli -mmcu=atmega32u4 /Users/user1/Downloads/lfkeyboards_lfkpad_ayout_numpad_6x4_mine-2.hex -v
    Teensy Loader, Command Line, Version 2.1
    Read "/Users/user1/Downloads/lfkeyboards_lfkpad_ayout_numpad_6x4_mine-2.hex": 21460 bytes, 66.5% usage
    Error opening HID Manager
    Unable to open device

System Information

• Operating system: macOS Mojave - 10.14.4
• QMK Toolbox version: 0.0.9 (1)

Additional Context

All the dependencies were installed via brew and are on most recent version.
I originally installed via cask but got the error so I uninstalled via cask and manually downloaded the file but received the same error.

I looked up the error and saw something about ATOM but nothing with a clean solution or a something I would know how to implement.

Start by reproducing the QMK Toolbox 0.0.9 flow on macOS Mojave with the provided teensy_loader_cli command and its “Error opening HID Manager” output. Read the Toolbox logs and the teensy_loader_cli HID interaction first; done means the connected Halfkay device opens successfully and the firmware flash proceeds without that error.