Char: Lordofools
Server: Elzowin
Party voted to continue, clicked yes then was outside of the instance and not in party finder.
When I reapplied to another party gave that error when the host pressed start.
Hello @lordofools ,
Greetings to you. 
I am sorry to know about the lost entry to the instance.
I request you to verify the game files and re log in and try.
If error persists I request you to kindly wait, as, we now have a system in place that will re-grant access to activities in-game that have weekly lockout timers, utilize tickets, or consume a daily bonus (Aura of Resonance) when a game server crash or outage occurs during player participation.
Please read the full statement here-
I hope this helps!
Take Care! 