Because theirs more empty seats than their is on a match day and some people have tried purchasing tickets using e ticket and it keeps conking out on them.
Is it possible that a lot of fans will be waiting to see the result of the first leg? Would you want to go if we're 3/4 nil down after the first game?
But that could be because every seat has to be sold for this game, unlike on usual matchdays. Though, cannot load the map at all. That was my thinking, until @Gally got to me with his jedi mind tricks...
I think this is exactly it. If we win tomorrow or even grab a draw then there will be a surge in ticket sales for next Fridays match.
If you are trying to buy for someone else online make sure you can manage tickets for them and not just assign tickets cause it might not let you buy them. We had a problem getting tickets for my lad in his season ticket seat till we worked out what the issue was. You have to send a request from one account to the other to let you change the settings.