The upstream repository is running nexus 3.71.0.6 and it is returning status 400 for the query and:
<m:error xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">
<m:code>NuGet.V2.Deprecated</m:code>
<m:message xml:lang="en-US">The combination of parameters provided to this OData endpoint is no longer supported. Please refer to the following URL for more information about this deprecation: https://aka.ms/nuget/odata-deprecation</m:message>
</m:error>
which I suppose is the primary issue here?