Error ad block (facebook ad and unity ad)

hello, I’m using Facebook ads and unity ads in my app.

when the screen starts it loads facebook interstitial ad. and when the user clicks on button then facebook ad shows and if Facebook ad failed then it shows unity ad.

now problem is when the screen starts if facebook ad load failed then it’ll load unity ad and shows directly without clicking the button. anyone has solution for that.

When fb ad failed to load call unity ad load ad

When button click
If unity ad is ready
Then show unity ad

I think load ad option not available in unity ad
It’ll auto load ad.

May be but showing ad is in your hand by using show unity ad block, when it is ready.