When trying to sign in to a Google app in Mailbird you get the error message: "You are trying to sign in from a browser or app that doesn't allow us to keep your account secure".
Google has decided they will no longer allow access to their services from browsers embedded in other apps, for security reasons, and is slowly rolling this out to their users.
If you're experiencing this, the only solution is to use the app in a normal browser outside of Mailbird. Unfortunately this is a Google decision outside of our control and it affects all apps using embedded browsers.
You can read more about the decision here:
Sadly the suggestions in the document does not apply to embedded apps so there is nothing we can do to fix the issue. The Google apps are still included in Mailbird for now as Google is not blocking access for all their users yet, but once they do we will have to remove the apps from Mailbird.