Explanation for non-German speakers. The article reports that in this general election an exceptionally high number of Germans living abroad cannot vote because either the vote by mail is too slow or the ballot doesn't arrive, at all. This time, because of shortened deadlines, the situation is so bad that constitutional lawsuits might follow.
For citizens abroad Germany only provides mail-in-ballot. Voting at embassies and consulates - something that e.g. Japan provides - is not available.