Hope this helps someone:
For me, using turbo tax premiere on MacOS, I was not able to connect to E*Trade at all. I entered the username and password straight from the MacOS keychain to avoid making mistakes and the "continue" button would not even enable (and show in black).
After talking with turbo tax support (and encouraging them to dig deeper with me), we found out that the button will only turn black when you enter the user name and password manually. Otherwise the software does not recognize the entry. After that it worked.
