Why is it that after being timed out I can't log back in?

This can be caused by the piled-up cache in your regular browser, @Jezzer. 

The error you're having with the subaccounts may be caused by the piled-up cache in your regular browser. A regular browser's cache stores temporary internet files from your browsing history. However, as it collects too many files, this may cause performance issues in your account.

I've got some steps to help fix this issue. First, you'll have to sign in to your QBO account using a private browser. This helps isolate the issue since it doesn’t store data in the cache. 

Here are the following keyboard shortcuts: 

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

Then, try to log in to your account. If it works, here's how to clear cache and cookies to fix issues when using QuickBooks Online. Restart your browser right after. 

Here's a guide on how to extend the timeout duration in QuickBooks Online for up to 3 hours: Change the timeout duration in QuickBooks Online. 

If you're facing issues with logging in to your account, follow these steps to recover your Intuit Account if you can’t sign in. 

Let me know if you need further assistance with logging in or any other issues. I am always here to help. Have a wonderful day!