Netflix Issue

It isn't a technical problem or something you can fix, unfortunately. With Netflix, they have limited access to display certain shows and seasons depending on where they are buying them from. With some shows such as from the BBC, you will often find seasons, and entire shows, vanishing for a few days, weeks, or even months before Netflix is able to renegotiate and make a deal and pay enough to air the episodes. So for now you will not be able to view the second season as Netflix's contract with the BBC likely has run out. But it may show up again any time, so keep an eye out for it.