Hi ctomfung, welcome to the WiiHacks community.
There could be several reasons for the issue you are experiencing :
- Some of your discs may be trucha signed in which case you would need to use GeckoOS to load the discs
- It could be Modchip firmware issue. You could try downloading the latest WiiKey firmware and config disc images from Wiikey.cn and see if it is recognized by your wii. If it is, then that means you have WiiKey and you then update firmware if it is not already updated.
- You could also try downgrading your Wii back to 3.2U using AnyRegionChanger, this will require you to have Homebrew channel installed first.