Docker repository authentication required

When I docker pull mcr.microsoft.com/dotnet/aspnet in log
admin org.sonatype.nexus.repository.docker.internal.V2Handlers - Error: HEAD /v2/mcr.microsoft.com/dotnet/aspnet/manifests/latest: 401 - org.sonatype.nexus.repository.docker.internal.V2Exception: authentication required
but i set user & pass in docker repo in section http Authentication section.
where is the problem ?!