Ad Error

I'm playing for the dungeon missions, and aside from the fact that a lot of ads pop up, there are times when no matter how long I wait for the ad, the 'X' button doesn't appear. Is it just me? I even waited for 5 minutes thinking it might be because the ad is long, but it didn't work, so I have to restart from the beginning again. ㅠ Where should I report this ad error? I've never had this problem with other games, so it's driving me crazy.