On my wireless filter list on the hub contains duplicate entries with an "invalid value" in the wireless radio column. These cannot be deleted! I also have a problem that people can't log in to my guest network.
You'd probably receive more help if this was posted in the Networking & Wifi section.
Have you tried resetting the hub back to factory settings?
If you haven't and you decide to perform this, make a note of any special settings you've set up.
Also make sure ensure you have a note of the default Network ID and password (they should be on a sticker on the base)
Have you enabled the Guest Network in the hub settings? Are you allowing it to broadcast the network name?