I agree with tones702, you should give the option to at least be able to put 1 minute between interstitials. It is an important issue.
You should implement it and after each user decides how much time to put.
Hello, the same thing is happening to me, a blank space is shown but the banner does not appear.
It happens to me in all the app that I create.
Is it an error when updating? How can we solve it ? Thank you !!!