Hi,
The label change is intended, it will not impact the server side whatsoever, it is definitely unrelated to the issue.
Try reinstalling the plugin first via the plugin manager, to make sure this is not a file corruption issue. Then, if the problem persists, then you will have to check the php error logs to see what triggers the 500 error. Error messages starting with 5xx are originating from the server side, so only the PHP error logs will help revealing the issue.