[FIXED] This issue has been fixed as of the May 3rd, 2018 maintenance. View the Patch Notes: here
We thank you for your patience.
The game team is aware that there is a current known issue regarding the Generation 20 quest, "Guardians," in which you are unable to reach the NPC Avelin's location in order to complete the quest requirement.
Fortunately, we can move your character to the correct location so you may proceed with this quest.
Please submit a ticket to us and be sure to include your character name and server. In the mean time, the game team is investigating a fix for this issue and we will update this article when the issue has been resolved.
Thank you for your patience and understanding.