Microsoft is deprecating Azure AD Graph API in June 2022, and as of June 30th, 2020, stopped adding new features to the API. See these Microsoft articles for more information:
Microsoft strongly recommends upgrading to Microsoft Graph API to access Azure AD APIs or APIs from other Microsoft services. Nintex K2 Cloud OAuth resources requiring access to the https://graph.windows.net API (Azure AD Graph), must be updated to use https://graph.microsoft.com (Microsoft Graph) as part of the migration from Azure AD Graph to Microsoft Graph. Nintex K2 Cloud Update 16 includes the code fixes necessary for this migration.
After the upgrade of your Nintex K2 Cloud environment to Update 16, the OAuth resources that require access to AAD Graph API will be updated to use Microsoft Graph API instead.
This will affect Package and Deployment tool and the workflows using the Azure Active Directory broker. These workflows can enter a failed state if the workflow executes a step that uses the broker after upgrade, but before a Global administrator in your organization re-consents to the Microsoft Graph permissions. These workflows will have to be manually repaired after upgrade and re-consent.
This will also let your users continue to package and deploy your solutions.
Follow these steps before the upgrade to Update 16, to grant Admin consent to the Microsoft Graph permissions.
Follow these steps after the upgrade to Update 16, in order to switch existing service instances to use https://graph.microsoft.com (Microsoft Graph API).
1. In K2 Management, browse to Integration > Service Instances and select the service instance using Azure Active Directory service type. Click Edit.
2. Update the OAuth Resource Audience to use https://graph.microsoft.com and click OK.