Test interstial ads is not loaded when i reopen my app

Hi I am doing an ad test on my app . I had put up ADmob interstial and banner ads
When i initialized the ads , banner ad is shown. Interstial ad is shown when the app is opened for the first tym . afterwards i left the app and entered the app again. this time banner app is shown bt interstial is nt shown after the time interval (120 s) i set . How can i solve this problem
Thanking you in advance if i get the solution

You are using wrong method to load and show ads. Search Community for correct method.
Remove clock blocks to show Interstitial Ads. Use When Ad Loaded to Show Interstitial Ad.

Welcome to the community.
Please change the category to monetization.

i dint get u ??

Use the show intrestial ad with when ad loaded event.
Or atleast show it after you confirm that ad has been loaded.