As a result of removing the monobook series skins, users using those skins will see a “blank page”. We’re working on resetting everyone’s preferences, but in the meantime please use the following workaround, as Gordon suggested. Here’s the fix:
You can fix the problem by going to this URL while logged in:
This will take you to your preferences page and temporarily override the skin. Once there, select one of the available skins and save your changes, which will update your preferences in our database.
We apologize for the inconvenience and hope you have had a spendid New Yahren so far.