Nintendo's servers are down. This problem is affecting real Wiis too.
If you need to do an online update specifically, you'll have to wait until Nintendo fix the problem. But if any system update is fine, you can right-click on a Wii game in Dolphin's game list and select Install System Update to get the update that comes with that disc.
If you need to do an online update specifically, you'll have to wait until Nintendo fix the problem. But if any system update is fine, you can right-click on a Wii game in Dolphin's game list and select Install System Update to get the update that comes with that disc.