NuGet enters a loop when you are not providing the "-Source <source name>" while trying to install a package.
Try adding this to the command and see if it works:
"Nuget.exe install <package name> -Source <source name>".
If this is not successful, open your NuGet.config file located in the following location: "C:Users<your user name>AppDataRoamingNuGet".
Please remove all the configuration in the file so that it looks like this:
<?xml version="1.0" encoding="utf-8"?>
Save the file with no configurations in it and add the new source.
"nuget sources Add -Name <source name of your choice> -Source <url to the repo>"
You can find the command in our wiki page "Publishing to a Local Repository".
After adding the source you will need to provide the credentials as well:
"nuget setapikey <username>:<password> -Source <source name from the previous command>".
To push or install a package, you will need to use the following command:
"nuget install <package name> -Source <source name from previous command>".