AAA, NAC, Guest Access & BYOD

I have enabled guest self-registration. How can i ensure that guest accounts expire by midnight each day?

We need to disable the expire_after field in the guest self registration form and set initial value of the expire_time field as shown below:

here the account is set ot expire at midnight on the next day. If we want the account to expire on the same day at 11:59, we can set the initial value to "23:59".