Ubuntu & dotnet restore : error NU1301: Unable to load the service index for source https://mycorporatenexus.org/repository/nuget.org-proxy/index.json

I am struggling in restoring a .NET solution on an ubuntu VM.

When I run the command dotnet restore I always get the error:

error NU1301: Unable to load the service index for source https://mycorporatenexus.org/repository/nuget.org-proxy/index.json

I can access the index via browser, I can download it with WGET. The corporate feed is public.

I run the command dotnet restore --verbose d and the nuget.config files are the right ones, the sources are the desired ones.

so far I tried to:

• setting the http and https proxy via nuget.config & via environment variables
• setting no_proxy via nuget.config & via environment variables
• verifying that root ca certificates are installed in ubuntu
• run the command with the highest level of detail

at the moment I have no idea on where the problem could lie. Can anyone suggest me a way to debug it further?

.NET SDK: Version:           8.0.302 Commit:            ef14e02af8 Workload version:  8.0.300-manifests.f6879a9a MSBuild version:   17.10.4+10fbfbf2eRuntime Environment: OS Name:     ubuntu OS Version:  22.04 OS Platform: Linux RID:         linux-x64 Base Path:   /usr/share/dotnet/sdk/8.0.302/