Retrieving and modifying options field of a connection now requires new scopes: read:connections_options and update:connections_options. These apply to https://{TENANT}.auth0.com/api/v2/connections and https://auth0.com/docs/api/management/v2/connections/get-connections-by-id.
To fix this, ensure that your auth0 application (e.g., machine-to-machine application) has those scopes/permissions for accessing auth0 management API. Go to your auth0 application’s API Access and look for the Auth0 Management API (or non-default ones if you have one) and select Edit.
Resources: