Admob looks for this file in the root of the pages. The problem with either gitlab or github is that you can create these pages for free, but you end up having a link like this:
https://accountName.github.io/projectName
Admob doesn't expect to have that /projectName at the end of .io and because of that, app-ads.txt is missing.
Is there any way to modify this url or change it in Admob? I guess I could by some domains but that's not what I'm looking for right now since I've got many open projects.