Can someone help me plse ?

Hello Satish, https://helm.datahubproject.io CA’s certificate is issued by let’s encrypt:

curl -vI <https://helm.datahubproject.io>
*   Trying 185.199.110.153:443...
* Connected to <http://helm.datahubproject.io|helm.datahubproject.io> (185.199.110.153) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*  CAfile: /etc/ssl/cert.pem
*  CApath: none
* (304) (OUT), TLS handshake, Client hello (1):
* (304) (IN), TLS handshake, Server hello (2):
* (304) (IN), TLS handshake, Unknown (8):
* (304) (IN), TLS handshake, Certificate (11):
* (304) (IN), TLS handshake, CERT verify (15):
* (304) (IN), TLS handshake, Finished (20):
* (304) (OUT), TLS handshake, Finished (20):
* SSL connection using TLSv1.3 / AEAD-CHACHA20-POLY1305-SHA256
* ALPN, server accepted to use h2
* Server certificate:
*  subject: CN=<http://helm.datahubproject.io|helm.datahubproject.io>
*  start date: Mar 31 20:12:09 2022 GMT
*  expire date: Jun 29 20:12:08 2022 GMT
*  subjectAltName: host "<http://helm.datahubproject.io|helm.datahubproject.io>" matched cert's "<http://helm.datahubproject.io|helm.datahubproject.io>"
*  issuer: C=US; O=Let's Encrypt; CN=R3 <--------- THIS LINE
*  SSL certificate verify ok.
* Using HTTP2, server supports multiplexing
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x13b80fa00)
> HEAD / HTTP/2
> Host: <http://helm.datahubproject.io|helm.datahubproject.io>
> user-agent: curl/7.79.1
> accept: */*
>
< HTTP/2 404
HTTP/2 404

It looks like your machine does not trust it, I would suggest following the steps defined here: https://www.codingmerc.com/blog/add-lets-encrypt-root-certificate-linux/