We're glad you've raised your concern here, @Ber145.
I understand the challenges you encountered for days now when trying to sign in to your QuickBooks Self-Employed (QBSE) account. Let me help you fix the error status 400 - Bad request page.
To see if this is a browser-related issue, let's perform some basic troubleshooting steps. The initial step is to log in to your QBSE account via a private browser. When running web-based programs, this doesn't store cache files that may cause odd behaviors.
Below are the shortcut keys you can use:
- Google Chrome: press Ctrl + Shift + N
- Mozilla Firefox: press Ctrl + Shift + P
- Microsoft Edge: press Ctrl + Shift + N
- Safari: press Command + Shift + N
If this works, clear the cache of your regular browser to eliminate piled-up data. If the issue persists, you can use another supported browser or device. It might be that the current one you're using has a temporary issue with the program.
After performing this, if the same error happens, I recommend contacting QBSE Contact Support. They can help you look for the root cause of the issue and find a fix.
You might want to learn how to integrate your bank in QBSE. Feel free to read this article: Connect bank and credit card accounts to QuickBooks Self-Employed.
For additional questions about signing in to QBSE, leave a comment below. I'll help you as soon as possible. Take care always,