MySQLRouter on Windows 10 Unable to connect to the metadata server

I have set up a set of three MySQL 8.0.17 databases using group replication. They are all on my Windows 10 PC, using ports 3306,3307,3308. I am now trying to set up mysqlrouter. I have installed it in c:/mysqlrouter/. But when I run: mysqlrouter --bootstrap root@localhost:3306 I simply get: Error: Unable to connect to the metadata server: Error connecting to MySQL server at 127.0.0.1:3306: Lost connection to MySQL server at 'waiting for initial communication packet', system error: 10060 (2013) This is the same on all three ports, and using each of the different users (localhost, 127.0.0.1 etc) I have confirmed that the MySQL user exists (I have root @ localhost / 127.0.0.1 / ::1 / % all set up) and I can login to MySQL using each of them. Is there something I need to configure? I can't see anything obvous in the documentation?