I am using Nexus 2.11.1 open source.
I've created a proxy repository https://repo.spring.io/libs-release/, I am not able to get the index and in routing it reads "Server proxied by M2Repository(id=XXXXX) proxy repository is not supported by automatic routing discovery"
I tried it with http://maven.springframework.org/snapshot as well, but its the same issue.
I was going through https://issues.sonatype.org/browse/NEXUS-5849, however, I could not get it working.
My intention is to create 3rd party proxy repositories and add them to Public group.