Why can't I create a new admin certificate?

When you try to create a new admin certificate, you see an error message similar to the following example.

You have reached the maximum number of admin certificates. To create a new admin certificate, you must remove an existing one by revoking a user's IAM admin permissions and then removing their entry from the `ibm-admin-cert` ClusterRoleBinding.

You have reached the limit of 50 admin certificates per cluster.

You must remove an existing admin certificate before you can add a new one.

To complete the following tasks, you must have the Administrator IAM access role for the cluster.

Log in to the CLI.
Remove the user's IAM access permissions.
Set the context for your cluster. Include the --admin option.
```
ibmcloud oc cluster config --cluster mycluster --admin
```
Edit the ibm-admin-cert ClusterRoleBinding file. The following command opens an editor in your terminal window.
```
oc edit clusterrolebinding ibm-admin-cert
```
In the ibm-admin-cert ClusterRoleBinding file, find the admin certificate to remove. If you logged in with a service ID, the name of the entry contains Service-ID-XX, with XX as the service ID to remove. Otherwise, the name of the entry contains IBMid-XX in the name, with XX as the user ID to remove.

The following entries show examples to remove.
```
- apiGroup: rbac.authorization.k8s.io
kind: User
name: iam-ServiceId-XXX-admin-<DATE>
```
```
- apiGroup: rbac.authorization.k8s.io
kind: User
name: IBMid-YYY-admin-<DATE>
```
Try again to create the admin certificate.