When you experience a blank screen for QuickBooks Online (QBO) login, you can perform some troubleshooting steps to isolate the issue. There are times that the browser is full of frequently accessed pages, thus causing some unusual responses to the system. You can log into your QuickBooks Online (QBO) account using a private browser (incognito).
Press Ctrl + Shift + N (Google Chrome)
Ctrl + Shift + P (Firefox)
Control + Option + P (Safari)
If you're able to access the QBO login page and sign in, return to your default browser and clear its cache and cookies. This will refresh the system and remove older data that causes viewing and performance issues. However, if the issue continues, I'd recommend using other supported browsers.
In the meantime, I'm adding this article to further guide you in effectively managing your business using QBO: Help Articles. It includes topics about account management, banking, and taxes to name a few.
Please know that you're always welcome to comment below if you have other concerns or follow-up inquiries about logging into your QBO account and managing the growth of your business. I'm just around to help. Take care.