SFB on Mac stuck while MS AutoUpdate tries to install version 16.23.64

This morning SFB cannot start since Microsoft AutoUpdate is trying to install version 16.23.64 and the process is stuck after downloading the actual update. The "overall" process bar is stuck at around 50% and the "Installing" is at 0%.

If I quit the Microsoft AutoUpdate program and launch SFB I get a window on the top right side saying "Updating Skype for Business" "Skype for Business will launch once the updates have finished installing", and it just stays there while nothing happens. CPU usage is at almost 0% and there is no Skype or MS process doing anything.

There must be an install/status file somewhere that's preventing the install process to continue/finish. I'm not sure what version is installed since I cannot check through the UI, nor I know what file has the version info. Last successful update was around 2 weeks ago.

What should I do / check ?

Thanks...