Could not validate app name Azure

I'm new to MS Azure. I've created a trial account but when trying to create a new Web App, both through the web portal and through VS2017, I'm getting the "Could not validate app name ".

1. I'm sure the name I'm giving is unique.
2. I've tried cleaning out cache\signing out and in etc. Exmaple #1 Example #2

What am I missing?

Thanks!