Hello there, @leonard.
Let me route you to the best available support so you'd be guided in verifying your account's status.
First, you can try accessing your account using a private or incognito window. This way, we can check if this a cache-related issue. Pilled up data from the browser can affect the performance of your QuickBooks Online (QBO) account. Here are the keyboard shortcuts in opening a private/incognito window:
If you're able to successfully log in to your account without getting the prompt, then, you'd want to clear your regular browser's cache. This will make your browser to start fresh and to function efficiently. However, if the issue persists, I suggest using other browsers.
On the other hand, you can follow the steps below to contact our Customer Service team from the (?) Help icon. Here's how:
Keep me posted by leaving your message through this post if you have follow-up questions. I'll be happy to help. Have a good one!