A Change of Heart

I'm having trouble delivering the mission A Change of Heart, it's stuck on the continue button and it won't deliver, what should I do?

There is many add-ons that can cause troubles related to quests, for exemple a corrupted weakaura may block you from sharing/abandoning a quest.
i will suggest that you turn off all add-ons and try again.
if the add-ons was not the cause you can delete the Cache folder located in the game's folder and run your game again.