Unity ads NOT working with test mode OFF.

Hi, i'm from Brazil and have a little Archer game not yet published in playstore, six months ago i integrated unity ads via the services window and everything was amazingly working, ads showed, both test and real ads and the dashboard was working nice and fine.

Then, it suddently stopped.

The test ads show in the real device correctly, but when i override the testmode OFF, advertisiment.isready() is always false.
Very very sometimes i can get 1 ad to show once in a week, its very inconsitent and i just want to know if the problem is with my code and setup OR is it that because my country is like tier 3 there are just to few advertisemnt campaings that want to show ads to a project that have like 4 users ( me , my mom, my dad and girlfriend kkk).

Thanks for anyone that want to help.

If there is any further information that i need to give in order to help solving this problem pls let me know.