The MSOL Sign-in Assistant link provided in the MFG documentation is to the release version that has compatibility issues with the MSOL Module for Windows PowerShell installer. Microsoft has released a BETA version of the MSOL Sign-in Assistant that is compatible with the MSOL Module for Windows PowerShell installer.
The following steps should resolve the issue:
1.) Uninstall the MSOL Sign-in Assistant that is currently installed.
3.) Download and install the MSOL Sign-in Assistant (64bit) from the following link:
4.) Download and install the MSOL Module for Windows PowerShell (64bit) using the link in the documentation, which is provided below for convenience: