Blueprint error on my platform waypoint system

I am not really sure what you are doing. But if it helps, I can show you a simple way I accomplished the same thing. I used an array to store the nav points and I just indexed through the array until I reached the end then I restarted the process to the beginning.
the process over.
Note: you may want to replace the delay with a timer.
Note: I added a “nav mesh bound volume” to the scene to use AI.