Pvp-I can't reactivate the track
There should be somewhere that will let you reset it.
If the “reactivate” button doesn’t appear in the top right corner of the track UI, it’s probably because you haven’t finished story mode for Sorrows Embrace since the PvP update was released. Completing the story dungeon before the patch came out does not count retroactively.
The reason you’re able to do some dungeon tracks (temporarily) without completing story mode is they’re on a rotation. Every 2 weeks a new dungeon reward track is available for all players, including those that have not completed story mode for that particular dungeon.