Seem we can not create a new pool any more. Always get the error say reach CPU core limit even on new account.
In my account all newly created batch-accounts/Pools now have a quota of 0 - probably that's why you got the message about the CPU core limit.
My existing batch-accounts/pools still have their original quotas -
If you have a working batch-account it's probably a good idea to keep re-using that account for now. I will contact the azure-support and check if they increase the quota on request.