@Ftd,

I would first try forgetting the network from your list of known networks on your phone and iPad and trying to reconnect, as this will refresh and credentials that may be causing the behavior. Are you able to see the extender's network in your list of wireless networks?

Do you know if you had configured any settings on your network such as the Allowlist? If so, I would recommend turning off the Private Addressing feature on your phone. The setting can be found in your phone's wireless settings while connected to the network.