Hi there, thanks for posting in the Community!

Let me help you sign back in to your QuickBooks Self Employed account. As per checking the screenshot you've tried signing in via a web browser. Are you able to access your account via the Self Employed mobile app? I'd recommend downloading the mobile app version to see if the issue persist or not.

Can we please try to clear cookies and cache on your browser and then follow the steps below:

1. On Keyboard, click Ctrl Shift Delete to bring up the pop-up window
2. Select the time range to be ALL Time
3. Select the checkbox for Cookies and Cache (rest of the list are optional)
4. Select Clear data
5. Sign out of QBSE account (if already signed in)
6. Sign back into QBSE account ttps://au.selfemployed.intuit.com/login to check if working

Furthermore, I can see there's a reported product investigation with the error you've reported INV-82584 QBSE AU Only: Unable to login through web browser, getting error - "An unknown error has occurred. Please try again later." and currently being worked on. I would recommend contacting directly our Live Chat support team. That way, they can escalate your account to our senior support team and get your details securely.

Post again in the Community if you have more questions about QuickBooks Online. The team is here to help you.