On WordPress Multisite the default setting for plugins is ‘disabled’.

This means your users won’t have access to the plugin admin panel inside their dashboard unless you first enable access to plugins network wide as follows:

1. Click on the Network Admin link in the drop down menu under My Sites in your toolbar.

2. Click on Settings in the Network Admin dashboard.
3. Select Enable administration menus for Plugins
4. Then click Save Changes

See Next:

Activating and Deactivating Plugins on a Per Site Basis