My guess is that you logged in using an old shortcut. Several years ago you could add the domain on the login URL so you didn't have to type in your complete username/domain. I'm not sure if that still works, but in any case my guess is that either a shortcut or maybe a cookie are causing that at the end of the URL. I do not see that with any of my three accounts at a couple of domains. Try this:
- Log out
- Manually enter https://www.fastmail.com in the URL bar (and make sure it doesn't get changed by any cached entries)
- Click the Fastmail icon or name in the upper left corner of the screen. The URL should be: https://www.fastmail.com/
- Click Log in in the upper right of the screen. The URL should be: https://www.fastmail.com/login/
- Enter your full login email and password and click Log in.
- You should be logged into your account. The URL should be: https://www.fastmail.com/mail/Inbox/?u=xxxxxxxx, where xxxxxxxx is a string which I believe is related to a cookie on your PC.
- The exact URL may depend on whether you have your login saved on that PC. I'm not sure and don't want to try all combinations.
Bill