Planners and users (direct reports) are all eligible but when you launch a form(s), no form(s) created [There were 0 plan(s) created.].
This might be because either the Planner or the users (direct reports) is/are not Valid EC Users.
To know if they are all valid EC users, raise an incident to Compensation Product Support provide the userid of the affected users so they can check it for you in Provisioning -> Manage Compensation -> Check Valid EC Users.
Once confirmed that the users are not valid EC users we'll need to make them valid EC users by doing an Import with the help of Employee Central Product Support Team. Raise an incident to ask assistance
2418247 - Eligibility Rules not being applied to all users in EC integrated template – Compensation
valid EC user, SourceofRecord, launch worksheet EC , KBA , LOD-SF-CMP-EC , EC data, config & settings within Compensation , Problem