Summarize the following:
In most cases, you may not have the permissions required to modify Content Lock settings. Content Lock is a feature of EE’s mobile network, and is not applicable when browsing the Web on third-party Wi-Fi networks.
Contact your account manager for help with resolving Content Lock issues if you have a corporate or business account with EE. Try viewing websites using a third-party Wi-Fi network if Content Lock cannot be disabled on your device.