Like many other users, Microsoft Sudoku will not let me login. Of course the game puts the blame on the Internet connection at my end when it appears to be the fault at Microsoft's end. All my other Microsoft games (Solitaire Collection, Minesweeper, Word Games, Mahjong, Jigsaw, Taptiles and Bingo) have no problems with login or with Internet connection.
This is not the first time Microsoft has had these type of problems with its games. They made a similar claim to me when I complained how their Solitaire Collection kept dropping its connection one day when there were several other gamers who had the same problem during one of its event competitions. The tech who replied back to me had the stupidity to suggest I connect to the Internet with a wired connection when the fault was clearly at Microsoft's end.
Please fix your game, Microsoft.