We usually do portal customization for the customers in trial accounts and we will use it for our proof of concept purpose. But we could not able to customize the portal and the previous option is not enabled now. Could you please let us if anything changed in the trial account access?
We don’t restrict portal customization based on trial account but we do based on the pricing plan of the account. You can view the plan details under Admin > Plans & Billings.
You can request for right plan that fits your development needs by submitting a request here: https://dev-assist.freshworks.com/support/catalog/items/43