If you are playing an event but the story progress is stuck (20%, 30%, 40%, etc.), check the quest icons on the left.

• Bright, colored icon — this is a main story quest.
  Completing it advances the story and increases event progress.

• Dim or grey icon — this is a side quest.
  It is optional and does not affect the main story progress.

👉 To continue the event story, focus on quests with colored icons.