I tried to run an example server from Milo OPC repository, and I put as endpoint the ip of the PLC. In the device, the name of the device is "MI_027859".
19:18:36.748 [main] WARN o.e.m.o.stack.core.util.EndpointUtil - Endpoint URL 'Illegal character in hostname at index 12: opc.tcp://MI_027859:12686/MI_027859' is not a valid URI: {}
java.net.URISyntaxException: Illegal character in hostname at index 12: opc.tcp://MI_027859:12686/MI_027859
at java.net.URI$Parser.fail(URI.java:2848)
at java.net.URI$Parser.parseHostname(URI.java:3387)
at java.net.URI$Parser.parseServer(URI.java:3236)
at java.net.URI$Parser.parseAuthority(URI.java:3155)
at java.net.URI$Parser.parseHierarchical(URI.java:3097)
at java.net.URI$Parser.parse(URI.java:3053)
at java.net.URI.parseServerAuthority(URI.java:915)