Your sentiments are valid about dealing with login problems and losing access for your users, @leeboy. Let's work together to troubleshoot these errors and get you back on track. 

I've checked the QuickBooks status page for any ongoing issues but found no reports of system problems.

One of the possible reasons why you're having trouble logging in to your QuickBooks Online (QBO) account and the disappearance of your user access can sometimes be caused by a stored cache and cookies in your browser. To verify, let's access your account using a private or incognito window. You can use these keyboard shortcuts to save time:

• Safari: Command + Shift + N
• Mozilla Firefox: CTRL + Shift + P
• Google Chrome and Microsoft Edge: CTRL + Shift + N

Once you're in incognito mode, log into your QBO account again. If you're able to log in, return to your regular browser and clear the cache to improve the program's performance. Alternatively, use other supported browsers. 

For more troubleshooting steps about sign-in issues, check out this article: Recover your Intuit Account if you can’t sign in

To regain your user's access to the account, I suggest letting them use a new email when logging in. Then, reinvite them to see if it'll work. 

If the error persists, it's best to contact our QuickBooks Support Team for further investigation. They'll be able to help you troubleshoot the login issues, restore access for your other users, and ensure that your account is set up correctly. They can accommodate you Mondays to Fridays from 6 AM to 6 PM PT and Saturdays from 6 AM to 3 PM PT.

You may also visit this page to further guide you in managing your company information, subscription, and login details: Account Management.

I'll hear you out if you have more questions about sign-in issues and managing users' access in QuickBooks. You can leave your reply below and I'll provide further help.