Cannot search hosted Maven repository on Nexus3


I am a complete newbie to Nexus3 Repository Manager, so please excuse the apparent stupidity of my question. My task is to set up an internal Maven repository for company libraries with proxy to the Maven Central. I’ve installed Nexus3 RM, set up the SSL, users and roles. I’ve deleted the nuget repos as our company does not use .net, and kept the maven-releases, maven-central and maven-snapshots. I’ve created a group repository for the maven-releases and maven-central. Then I set up a task to publish the indexer files. From that time on I can retrieve the /.index file and /.index/, but any other file listed in the .index page is responded with 404 Not Found. But that holds only for the group repository of (central & releases). The central repository behaves exactly alike to the group repository (.index and retrievable, others not), but all hosted repositories do not produce any .index (404 Not Found).
When I set up my local maven to address the group repository as a mirror to the central, it can build any project with dependencies both from central and from the maven-releases. The trouble is that I cannot search for dependencies from Netbeans (currently 11.3). NB transfers the index, unpacks it, installs it (about 1.5GB) and is able to search it - excluding the maven-releases. No internal artifacts are found, just the central ones.
Can anybody help me to resolve the issue? Thanks a lot.

Hi there,
found the way out. There is still a thing that is puzzling me: when I create a group repository grouping a proxy and a hosted one, it somehow chooses the index of either one and presents it regardless of the other.
If you are using NetBeans to search and download artifacts both from the public central and from you private repository, create two mirrors and their corresponding credentials settings in your settings.xml of Maven. Aggregate those into a single profile and activate it. Delete all files/folders under your netbeans cache/mavenindex and cache/mavecachedirs. Remove the local maven cache (if suitable).
On Windows, NetBeans 11.3 simply took the settings.xml and downloaded the indexes.
On Fedora I had an authentication issue and I had to set up the Maven repositories manually in Services tab -> Maven Repositories. The credentials can be put right into the URL like
In either case we used a separate maven installation instead of the NB-bundled one.