Sharing a document library with external users

Is anyone running into problems with external user access on SharePoint Online sites since yesterday (15 Sep 2016)? I have my gmail address set as alias on my outlook.com account and I've used this to access SPO site as external user in the past. I tried sharing a new SPO site to me gmail address and got a email invite in my gmail. When I try to access it using me gmail address as user name and its password (in the login page, I choose 'Microsoft Account' from the available options 'Microsoft account' & 'Organizational account'), I get redirect to outlook.com login page and there after an error "Your account or password is incorrect. If you don't remember your password, reset it now"...

This is insane. I know my gmail password and I'm logged into it. Just for troubleshooting, When I clicked "Create a Microsoft account, it's quick and easy!" on the 'Welcome to SharePoint Online page" and entered by gmail address, I got an immediate response indicating 'your@gmail.com is already a Microsoft account.' (confirming that the alias is valid)....