Hi,
you may check the following:
run the configuration Manager console on the SCCM server.
you need to go to the top-level site server before you can modify those options. In my case, I have to go to the CAS so going to any of the primary's it'll be greyed out.
make sure under security that your account, or the RBAC group your account uses for access has "full admin" with the security scope set to "all". If it is just set to default you can have issues with some of the cloud features.
That is, the account shoiuld have permissions to all instances under security scopes.
log in with the account that we installed Config Manager with to be able to "Configure Cloud Attach". None of the "full administrators" could do it except for the service account we installed it with.
best regards