に同意しなかった

did not agree to

→ に
phrase Rare #38,303
did not agree to Used after a proposal, plan, matter, or decision to say that someone did not agree to it or consent to it.
JA: 彼はその条件に同意しなかった。
EN: He did not agree to those conditions.

彼はその件について我々に同意しなかった

He didn't agree with us about that matter.

彼女はその提案に同意しなかった

She did not agree to the proposal.

ボブその計画に同意しなかった

Bob did not agree to the plan.