Hello,
I'm using the Enpass chrome extension for Mac, so there exists some pages where Enpass extension doesn't work as expected. The user is not copied to the field, but the password does without any issue. The workflow for this page is similar to Amazon, where first is shown a field for the user name, then after submit there is shown other page with the password field.
I can't paste the URL because your forum complains about spam.
I hope you can fix this.
Best regards.