Thanks for coming back with an update, @Ophus! I appreciate you trying that step and changing your username. 

I have double-checked and as of now, there aren't any known issues with this login problem. If you've already tried clearing cache and cookies and trying a new browser after changing your username, I'd recommend reaching out to support. 

Here's an article to walk you through your options: Contact QuickBooks Time Support.

I know it can be inconvenient to reach out to support but I'm confident they can look into this further and get the information they need to investigate further. As always, any questions you have, please feel free to reply to this post. We're all eager to help in any way we can!