The error is sometimes caused by too much data in your browser. Let's identify if this is a browser-related issue.
You'll have to use an incognito window when accessing the bank register to disable the cache on your browser. To do this, you can follow the shortcut keys below:
You can go back to your original browser and clear cache. Clearing the cache helps your browser work well. You can also use another compatible browser.
Let me know how the basic troubleshooting steps work on you. I'll be right here in case you need more help with QuickBooks.