One or more clarification cases are locked by different users

What causes this issue?

You attempted to lock one or more clarification cases. At least one
case has been locked by a different user. You will see that these cases
are locked by looking at their status in the refreshed list view.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

If you want to process these cases yourself, display the name of the
processor who has locked them and have the person release them.

Error message extract from SAP system. Copyright SAP SE.