A typical browser's cache stores data from previous websites you've visited. However, as it collects information, it might cause display issues in QuickBooks Online. This might be the reason you get a blank page when printing bank reconciliation.
I've got some steps to help resolve this issue. I suggest to access your QuickBooks account through a private browser. This is a good way to isolate the problem since it doesn't store data in the cache. Please follow the keyboard shortcuts for your two browsers:
For Internet Explorer of Firefox, press Ctrl + Shift + P.
For Chrome, press Ctrl + Shift + N.
For Safari, hold down Command + Shift + N.
From there, go back to the reconciliation page then, print it. If you're able to print a bank reconciliation without any issue, clear the cache of your regular browser. This eliminates the stored files so it helps the browser to function efficiently. If not, use other supported browsers.