I can’t start the “Breaking the Lightbreaker“ storyline, Lyana Darksorrow has no quest, I can’t complete the achievement. I am a Dracthyr, Broken Isles 5 maps I begin from Suramar. Someone shared this mission to me, it said “the mission doesn’t accept to your class”, I think it’s a bug, Dracthyr only.
Some of the Suramar quest chains have opaque requirements to begin them, so you can try working on other quests there to see if it becomes available later.
However, given the error message you got when you tried to have the quest shared, it’s probably a bug, so it would be a good idea to report it as such either using the in game tool from the help menu or by posting in the bug report forum.
Yup, I am a new Dracthyr, and I can’t start the quest. I have nightfallen but not forgotten, all of the rest of Good Suramaritan, and revered with the nightfallen.