The availability levels are activated by default and visible in the online store.
But if an availability level was deactivated for some reason, then products with this availability level will no longer be visible in the online store.
So if an item isn’t visible in your online store, then check to make sure the availability level is activated for the store.
This setting only affects older systems
In new systems, this setting is obsolete and is no longer displayed. We recommend that you check whether you have this setting in your system. If so, activate the setting.
Activating availabilities for the store:
If available, go to Setup » Client » [Select client] » Item layouts » Availability.
Press and hold Ctrl or Cmd and select the availability options.
Save () the settings.