I get a http 400 bad request error when I try to sign into my quickbooks self employed account. Can someone help me?

I can share some troubleshooting steps to help you fix the error so you can successfully log into your QuickBooks Self-Employed (QBSE) account, @cnllusher.

The error HTTP Status 400 - Bad Request prompts when the connection with our server is interrupted or corrupted. To rectify this, open your account using a private or incognito window. It 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

If it works in incognito, return to your regular browser and clear its cache. The system occasionally behaves strangely when the browser frequently accesses pages. It could be due to corrupted cache files in your browser. Otherwise, you can try other supported browsers to help narrow down the cause of this behavior. Also if you have other devices, try and see if you can access your account.

I'm adding this article to learn more about QBSE and how it differs from other versions of QuickBooks Online: What is QuickBooks Self-Employed?

Let me know in the comments below if you have other questions or concerns about signing into your QuickBooks account. I'll be around to lend a hand.