I wanted to take the sleeper Hamburg - Stockholm in July, and the superbly helpful Man In Seat 61 points me to book via SJ's website. However, all connections in June onwards, both daytime and sleeper, come up as "not available". There are some sleeper prices shown in April, but daytime again comes up "not available". Am I trying to book too early, or is there some reason they're not running, like major infrastructure works hitting this summer? I don't think they are sold out as I did see one service a few days in the future that explicitly said "sold out" next to it...