Chirpstack installation on New Ubuntu server

after running these commands i get a certificate error and i am stuck now :

  • Set up the key for the ChirpStack repository:
    sudo apt-key adv --keyserver --recv-keys
  • sudo echo “deb Index of /packages/4.x/deb/ stable main” |
    sudo tee /etc/apt/sources.list.d/chirpstack.list
  • sudo apt update

I get this error :
Err:1 Index of /packages/4.x/deb/ stable main
Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. The name in the certificate does not match the expected. Could not handshake: Error in the certificate verification. [IP: 443]
Hit:5 Index of /ubuntu noble-security InRelease

Most likely, you need to update the CA certificate bundle on your server. Because of the outdated CA certificate bundle on your server, the server is unable to validate the authenticity of the server certificate.

This was a brand new Ubuntu installation ? how can i manually update that CA certificate bundle ?
I am not a Ubuntu professional.