Admob Ad-unit ads serving issue

Discuss
#1

3-4 days ago I created Ad-unit for my new App but ad-unit is still not serving ads.
Anyone faced similar issue?

#2

Use ad failed to load block to know problem.

#3

Test ads unit are working, problem is with ad mob ad-unit

#4

Check your admob dashboard, is there any restrictions imposed on your account like ad serving limit or any other?

#5

Nothing, no restriction

#6

I created a campaign, ad unit showing campaign ads but not real ads.
Anyone faced this issue?