You can’t override Locked policies in Linewize Filter with Classwize Rules. If you create a rule that contradicts a Locked policy in Linewize Filter, the rule will only work for students who aren’t affected by the Locked policy.
Example
Your school has a Locked policy that blocks YouTube for some students. If you make a Classwize rule to allow YouTube, only students not affected by the Locked policy will have access to YouTube.
If all students need access to YouTube, you must contact your school’s IT Support.