Cannot install from command line

Trying to install to a new laptop - install the .NET 5.0.400 SDK and get the following:

dotnet tool install -g dotnet-repl

error NU1100: Unable to resolve 'dotnet-repl (>= 0.0.0)' for 'net5.0'.
error NU1100: Unable to resolve 'dotnet-repl (>= 0.0.0)' for 'net5.0/any'.
The tool package could not be restored.
Tool 'dotnet-repl' failed to install. This failure may have been caused by:

* You are attempting to install a preview release and did not use the --version option to specify the version.
* A package by this name was found, but it was not a .NET tool.
* The required NuGet feed cannot be accessed, perhaps because of an Internet connection problem.
* You mistyped the name of the tool.