Let's work together and get this issue resolved. To resolve this issue, I recommend clearing your browsing data. Clearing your file data will help QuickBooks load as a fresh new page to help fix any glitches that are occurring within your account. Here's how:
Go to the Three Vertical Dots (Menu/Settings) in the top right-hand corner.
Select History and then History again.
Press Clear Browsing Data on the left-hand side of the screen.
In the "Time Range" section, choose All Time.
Hit Clear Data.
Afterward, sign back into your QuickBooks Online account and try to print the Bank Reconciliation report again.
Allow me to step in and help you further with printing your reconciliation report. Since the troubleshooting steps that they've provided didn't work, I'd recommend uninstalling and reinstalling the app, then log back into your QuickBooks Online account and see if you're able to print the report.