How can accountant log in when it keeps asking him to re-register and then not recognising his email address?

Hi there, robguestcarpentr. 

Handing your log in issue is my top priority. In the meantime, let’s perform some basic troubleshooting so you can access your account.

If you can't access the Sign In page in logging in to your account, we need to check first if your browser is compatible with QBO. Here's how:

1. Go to https://fixit.intuit.com. If you see a red warning icon, you need to update your browser’s settings.
2. Select the button under the warning, then follow the steps provided.

Then, try signing in to QBO using a private or incognito window. This mode doesn't use the existing cache data and helps us confirm browser-related issues.

Here's how:

• For Google Chrome browser: Ctrl + Shift + N
• For Mozilla Firefox browser: Ctrl + Shift + P
• For Safari browser: Command + Option + P

If it works, go back to your regular browser and clear the cache to delete those temporarily stored files and browsing history. The overtime collection of data can create corruption, however, removing this should fix the issue. You can also use other supported, up-to-date browsers to roll out the possibility of a browser-related issue.

For other troubleshooting solutions, see Can’t access the Sign In page article for more details.  

I've got a link here that provides you with articles about managing your Intuit account: Account management gathers topics for your Intuit Account. 

Please update me once you have tried the steps. I'll be more than happy to assist you further. Have a great day and stay safe!