Trying to federate Apple School Manger with Google Workspace

I am trying to have ASM automatically pull our users from Google Workspace. This should be a simplle process but I am getting an error before even login in.

So in ASM I click on preferences > Accounts > Edit (under Federated Authentication)

Click on Google Workspace > Connect

Then click 'Sign in With Google'

I then get the following error box... (????? = removed my details)

Authorisation Error

Error 400: admin_policy_enforced

Access to your account data is restricted by policies within your organisation. Please contact the administrator of your organisation for more information.

If you’re the app developer, make sure that these request details comply with Google policies.

access_type: offline

response_type: code

trampoline: 1

redirect_uri: https://?????????

state: eyJjb??????????

nonce: 49?????????

prompt: consent

client_id: 1????????????

scope: openid https://www.googleapis.com/auth/userinfo.profile https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/admin.directory.user.readonly https://www.googleapis.com/auth/admin.reports.audit.readonly https://www.googleapis.com/auth/admin.directory.domain.readonly

Any idea how to fix this issue?