Unable to use harbor as a chart library.

[root@node5 ~]# helm version
version.BuildInfo{Version:"v3.11.0", GitCommit:"472c5736ab01133de504a826bd9ee12cbe4e7904", GitTreeState:"clean", GoVersion:"go1.18.10"}
[root@node5 ~]#
[root@node5 ~]#
[root@node5 ~]# cd /root/.local/share/helm/plugins/helm-push/
[root@node5 helm-push]#
[root@node5 helm-push]# helm  plugin list
NAME    VERSION DESCRIPTION
cm-push 0.10.3  Push chart package to ChartMuseum
[root@node5 helm-push]# helm repo add  --username admin --password Harbor12345 harbor http://harbor.dockerregistry.com/helm-chart/chartrepo/library
Error: looks like "http://harbor.dockerregistry.com/helm-chart/chartrepo/library" is not a valid chart repository or cannot be reached: error unmarshaling JSON: while decoding JSON: json: cannot unmarshal string into Go value of type repo.IndexFile

helm added harbor as a chart library, does harbor have to be https?