Coupling clusters doesn't work

[JJWTimmer]

Trying to couple clusters, I see this in the logs and nothing happens:

2020-08-06 11:34:24,662 Status code: 404
2020-08-06 11:34:24,663 {"errorResponse":{"statusCode":"404", "status":"Not Found", "messageCode":"", "message":"URI /manage/v2/cluster_names does not exist."}}