What Happens When Guest User's 30-Day Trial Expires?

Guest User's trial period starts on the date when that user is invited to the guest space and log in to that space, and the trial remains valid for 30 days.

When the 30-day trial expires, that guest user's license status is automatically changed from "Trial" to "Required".

You need to purchase the Guest User option if you continue to use the guest user.
How to Purchase the Guest User Option

Service will not automatically be charged even after the license status is changed to "Required".
The guest user can continue to access the guest space to use the service.

If you do not need the guest user, deactivate that guest user.
Deactivating Guest Users