I was able to play pre-roll VAST tag only once, I'm unable to play it again.
I have created a player and added the DFP VAST tag. Went into the content, clicked on the embed tag icon, was able to see my DFP hosted pre-roll ad. But this happened only once.
When I play the video again my ad doesn't appear. There is no frequency restriction in DFP.
Any help will be appreciated!