DELETE for /runtime/process-instances/{processInstanceId} is not available

When I use /runtime/process-instances/{processInstanceId} to delete a process instance, I get the following error:

But the ProcessInstanceSource code does have this interface.

Please tell me where the problem might be.

You are passing the id as a parameter, after the ?. See the line you’ve drawn a red arrow to: it needs to be the id behind the /, like /

Thanks for your kind help to solve this problem