Yesterday I attempted to upgrade the Zooz 800 Zwave USB firmware but that failed both directly in HA and also using the Simplicity software.
Though everything worked after the failed upgrade, overnight my Zwave stopped working. I tried a restart and also a restore of latest backup but neither did the job. I was not at home at the time and used the HA App on my Iphone. Finally I remembered that I am using a TP Link plug to connect the Yellow Box and using the Kasa App on my phone I did a power cycle and that resolved the issue with Zwave coming back.