You must publish plan categories so that they appear in the Category drop-down list while adding or editing subscription plans.
You can publish a plan category by selecting Yes in the Published radio button while adding or editing a plan category. Alternatively, you can perform the following steps to publish an already existing plan category.
To publish a plan category:
1. Navigate to Components -> .Mighty Membership -> Plan Categories in the Joomla global menu. The Category Manager [jcs] page appears and displays the list of existing plan categories.
2. Select the check box corresponding to the plan category you want to publish. Click the Publish button  in the toolbar, as shown in the following figure:
A tick mark appears under the Published column corresponding to the category you published.
To unpublish a plan category, select the category and click the Unpublish button in the toolbar.