While creating Page Template (If you are new to Dynamics 365 portal, you can check about Page Template here) in Dynamics 365 portal, I noticed the type validation was not working (It should hide Rewrite Url field when Web Template is selected under Type field).
Please refer our earlier article for setting up Dynamics 365 trial if you want to set up a Dynamics 365 trial and you can refer this KB to provision portal in your trial.
After activating above business rule Type validation started working fine.
Hope it will help someone !!