Same here.
Today, I was asked to allow infinitode2 to gather information which I declined as I usually do since I expected to get random ads and not personalized ads but I don't get any at all any more. Not sure if that is the cause of the issue but I also didn't find a setting inside infinitode2 to grant access or in the app settings since there are no permissions to set there at all.

Access can't be granted if you have once declined it, you'll have to re-install the game for that.
As for "why ads are not being shown" - in theory, you could see a non-relevant, random ads, but in reality nobody wants to spend money showing ads to the people who are not interested in them. So basically declining the tracking means nobody wants to show you ads anymore, and you can't view rewarding ads because there's nothing to show.
I can't change anything about it, sorry - that's a modern reality. In the ol' days all of the ads were personalized (and worked)