deleted 0 orders

Just installed the plugin exactly as described. (I need to delete all orders from my staging site in order to give access to externals).
I found the button to delete all orders in the woocommerce -> status -> tools section.
So there I clicked the button, but “0 orders werde deleted”, although there are about 10.000 orders in my staging site (this is also why I need a plugin to delete them).
I first thought it may happen because the site was in maintenance mode, I deactivated the maintenance mode, deleted the cache, transients etc. and then tried again: “0 orders were deleted”.
As there are no options or anything where I can see why the plugin didn’t work on my staging site (there is also no log), I stand helpless.
Will deinstall it.