Cannot find DEB package in APT repository

Sonatype Nexus Repository
1

I have created an APT repository in Nexus 3.38.

I followed the instructions from this page
https://help.sonatype.com/repomanager3/nexus-repository-administration/formats/apt-repositories

I have uploaded 2 deb files into this APT repository. Though when adding this repository on a debian distribution it cannot find them using neither apt-get install nor apt-cache search.
The linux distribution I am running (in docker) is debian 11 (bullseye).

I added the APT Nexus repository to the file /etc/apt/sources.list

# deb http://snapshot.debian.org/archive/debian/20220125T000000Z bullseye main
deb http://deb.debian.org/debian bullseye main
# deb http://snapshot.debian.org/archive/debian-security/20220125T000000Z bullseye-security main
deb http://security.debian.org/debian-security bullseye-security main
# deb http://snapshot.debian.org/archive/debian/20220125T000000Z bullseye-updates main
deb http://deb.debian.org/debian bullseye-updates main
deb https://nexus.company.com:8443/repository/inhouse-deb bullseye main

Running apt-get update I get this message about the Nexus APT repository

E: The repository 'https://nexus.company.com:8443/repository/inhouse-deb bullseye Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.

I removed all files under /var/lib/apt/lists/.
Then re-run apt-get update

root@b791388fbb47:/home/build# apt-get update
Get:1 http://deb.debian.org/debian bullseye InRelease [116 kB]
Get:2 http://deb.debian.org/debian bullseye-updates InRelease [39.4 kB]                                                                               
Get:3 http://security.debian.org/debian-security bullseye-security InRelease [44.1 kB]                                   
Ign:4 https://nexus.company.com:8443/repository/inhouse-deb bullseye InRelease                                           
Err:5 https://nexus.company.com:8443/repository/inhouse-deb bullseye Release                                             
  404  dists/bullseye/Release [IP: 111.222.33.44 8443]
Get:6 http://deb.debian.org/debian bullseye/main arm64 Packages [8070 kB]
Get:7 http://deb.debian.org/debian bullseye-updates/main arm64 Packages [2600 B]
Get:8 https://dl.cloudsmith.io/public/machinekit/machinekit-hal/deb/debian bullseye InRelease [4976 B]                                                
Get:9 http://security.debian.org/debian-security bullseye-security/main arm64 Packages [160 kB]                                                       
Get:10 https://dl.cloudsmith.io/public/machinekit/machinekit-hal/deb/debian bullseye/main arm64 Packages [32.3 kB]                                    
Reading package lists... Done                                                                                                                         
E: The repository 'https://nexus.company.com:8443/repository/inhouse-deb bullseye Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
2

Your issue is right there in the output:

Apt can’t verify the certificate chain in your Nexus install. The reasons for this can be many (none anything to do with Nexus per-se). Since you’re using https to get to your repository, my guess is that the TLS cert can’t be verified. My guesses as to why are:

  1. You use a self-signed cert, so will need to put the public bit of the root CA cert into the Ubuntu cert store
  2. You use a public cert, but haven’t put the full chain into the TLS config on your nexus server.

My knowledge is less certain, but it could also be that you need to add the public bit of the repository signing key to the Apt trust store.