If your wordpress is a multisite then the DiscourseConnect Client tab will not be available at all.
Because Multisite setups change how routes are handled, opening up various potential issues with the route handling required for using Discourse as the identity provider. We may revisit this at some point, but it’s not currently a priority.
If you’re considering integrating Discourse users with multiple Wordpress sites I suggest you consider a dedicated identity solution such as auth0.com, which works with both Wordpress and Discourse out of the box.