に失敗した

failed at

→ に
phrase Common #6,162
failed at Used after a noun or noun-like phrase to say that someone failed at or was unsuccessful in doing something. With a verb, use the noun form with こと, as in 考慮に入れることに失敗した (failed to take into consideration).
JA: 彼は面接に失敗した。
EN: He failed the interview.

私は企てに失敗した

I failed in my scheme.

彼の父親が大変がっかりしたのは彼がその計画に失敗したことだった

What greatly disappointed his father was that he had failed at the plan.

一行はその山登山に失敗した

The group failed in their attempt to climb the mountain.

彼女がテストに失敗したとは気の毒

It's too bad she failed the test.

彼女はイギリス海峡泳いで渡るという試みに失敗した

She failed in her attempt to swim across the English Channel.

なんでトムビジネスに失敗した

Why did Tom’s business fail?

どうして入試に失敗したのですか

Why did you fail the entrance exam?

ケーキ作りに失敗した

I failed to make the cake.

トム禁煙に失敗した

Tom failed to quit smoking.

最初私はそのテストに失敗した

At first, I failed the test.