Unable to Sign In to QuickBooks Online Accountant – Redirected to "Thank You for Your Patience" Page / RPS_LOCKOUT

I am unable to sign in to my QuickBooks Online Accountant (QBOA) account. After entering my email address and password, I am not taken to my account. Instead, I am redirected to a page that says:

 

"Thank you for your patience. We have received your request and will process your sign-up shortly."

Previously, I also encountered a redirect to a URL containing the error code RPS_LOCKOUT.

I have already tried:

• Signing in using different browsers.
• Using Incognito/Private mode.
• Clearing my browser cache and cookies.
• Resetting my password.

The issue persists, and I cannot access my QBOA account.

Additionally, I am unable to contact QuickBooks Support via live chat because it requires me to sign in first, which is not possible due to this issue.