Every time I use Fandom without logging in, I will be faced with similar experience. A pop-up video with ads about the content it tried to promote (sometimes related to the content of the Wiki I visited, but mostly not) will play automatically, and I have to stop it every time.

As I am a contributor to some of the Fandom Wiki, I have to log in in order to make the promoted video goes away, which it did. But logging in in order to get rid of it is not a solution to this. Video shouldn't be popped up like this, let alone played automatically. I would tolerate a static ad to some degree, but this is not what I'm willing to.