I use the google login for Trello, and have used the app in the past just fine, but whatever update or problem came up has caused me to have to use the browser.
I load the app and hit continue, then sign in. It brings me to a login screen w/ "login with google" as an option in addition to the regular password/username.
I click it and sign in, and it gives me
"
You are trying to sign in from a browser or app that doesn't allow us to keep your account secure.
Try using a different browser. Learn more
"
ETA: This is for the Windows 10 Desktop App, not in a browser