The armclient azlogin command relies on the a fixed path to the az command (found in AzAuthHelper.cs. However, this means that if the azure CLI is installed as a 64-bit program (and thus located in C:\Program Files\Microsoft SDKs\Azure\CLI2\wbin\az.cmd), the command fails with the error Azure cli is required.
Ideally, the az command should be looked up from the environment's path, rather than relying on a static location.