Web editor fails to open when trying to resolve merge conflicts

I am unable to use the GitHub web editor to resolve merge conflicts on my remote branches. When I click “Resolve conflicts”, the page tries to load the editor but immediately redirects back to the previous page without opening anything.

This issue started about three days ago, after I enabled some branch protection rulesets. Before that, everything worked normally.

**Steps to reproduce:**

Go to a pull request with merge conflicts

Click `Resolve conflicts`

Page flashes the editor for a moment

Redirects back to the PR page with no editor and no error message

**Expected behavior:**
The merge conflict editor should open normally so I can resolve conflicts directly in the browser.

Actual behavior:
The editor never loads. It redirects back instantly with no error message.

**Additional notes:**
– Issue persists across browsers
– Started happening only after enabling branch protection rulesets
– No changes were made to repository permissions

Please advise if branch protection rules are blocking the web editor or if this is a bug.

ソースファイルもテストも特定されていません。まず、マージコンフリクトのある pull request で障害を再現し、その後、ブランチ保護ルールセットを有効にする前後で、ブラウザー間の動作を比較してください。Resolve conflicts アクションが Web エディターを正常に開き、リダイレクトされずにコンフリクトを解決できれば完了です。

索引モデルが issue の本文から書いたものです。