【トラブル対応】OAuthURIがURI検証ルールに準拠していない

こんにちは。
Googleから「プロジェクトの非アクティブな登録済み OAuthURI は、URI検証ルールに準拠していないため、2021年7月12日までにGoogleDeveloperConsoleから削除されます。」という怖いメールが届きました。

なんかよくわからないけど、すぐに対応しないと…

Hello Google Developer,

We are writing to let you know that you have inactive OAuth redirect URIs and JavaScript origins in your Google Cloud project that are not in compliance with Google’s OAuth URI validation rules.

On July 12, 2021, we will remove all inactive URIs that are invalid.
On September 13, 2021, we will remove all URIs that are not in compliance with redirect URIs and Javascript origins rules (including formerly inactive URIs trying to become active).
What do I need to do to be compliant?
If these inactive OAuth redirect URIs and JavaScript origins are no longer needed, you can remove them from your Google Cloud project. If they remain inactive, they will be automatically deleted after July 12, 2021.
If your app still needs to use these URIs, please update your app and OAuth configuration from the Google Developer Console to use redirect URIs or JavaScript origins that are compliant with the OAuth URI validation rules by September 13, 2021.
The following Google Cloud project(s), which has/have registered OAuth redirect URIs and JavaScript origins without usage for over 90 days, and which will be removed by July 12, 2021:

Project ID: XXXXX
Client: XXXXX
URI: http://www.XXXXX
If you have any questions or concerns regarding these changes, please review the documentation provided above in this email.

Sincerely,

The Google Developer Team

GoogleCloudPlatformにて[認証情報]を確認するとGoogleCalendarの変更をプッシュ通知する設定をしているものがあり、そのURLがhttpだったのがダメだったようです。httpsに修正して完了です。