How to require enrollment in plan type

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I have set the plan type to have a minimum plan enrollment = 1

Once this is set, when i evaluate life event i get: 
You need to select more options to enroll in this plan. Select at least 1 options. (BEN-990184)
The plan name is Preferred Benefit Dental. You selected 0 options.

How do I make a plan type have a required enrollment another way to avoid the error above?

Thank you!