Hey @mreilaender - thanks for reporting this! if you upgrade Mailspring to the latest version (1.10.5), it’ll work correctly. We updated the app to support Google’s new security requirements a couple months ago. Thanks!
I am getting this error too. It’s using Oauth so I am unsure why Google is blocking it. Google doesn’t allow you to enable “Less secure apps” anymore. It’s blocked on personal as well.
Setup MailSpring account using IMAP (not the GMAIL option)
Put in your gmail address but for password you need to use a special password that Google creates for you to use with Mailspring.
Setup done!
To create the password for Mailspring, login to your Google Account associated with the gmail you want to setup and go to this link: https://myaccount.google.com/apppasswords
This will give you a special password for use with Mailspring specifically.