When connecting Azure DevOps, you may receive the following error:
Your Azure DevOps environment is not set up to allow third-party OAuth integrations
To enable access for third-party applications, Navigate to your organization settings in Azure DevOps and select "policies" from the left side menu.
On this page there is a setting named "Third-party application access via OAuth" . Enable this setting, and attempt to reconnect your Azure DevOps integration in Vanta: