scenario:
I forgot to call you last night so I call you explaining to you the reason on phone now.

case 1:
on the phone, I said:
Sorry, I forgot calling you last night.

case 2:
on the phone, I said:
Sorry, I had forgotten calling you.

In case 1, the past tense is correctly used because of the "last night"
How about case 2. Is it right?
Waiting for your urgent help, thanks.