I'm here to help make sure that you can open your memorized reports in QuickBooks Online (QBO).
I tried on my end, and I was able to open my sample memorized reports. I also checked if there's an ongoing issue about this but there isn't currently one. Just to clarify, did you receive any error messages? Any additional information will be much appreciated.
In the meantime, let's perform some troubleshooting steps that can help us isolate this. Try logging into your QBO account using a different or a private browser. There are times that the browser is full of frequently accessed page resources, thus causing some errors and/or unusual responses.
To use a private browser, here's how:
On your keyboard, press Ctrl + Shift + N (Google Chrome).
Ctrl + Shift + P (Firefox or Internet Explorer).
Control + Option + P (Safari).
Once logged in, go back and try to open your memorized reports again to double-check. For your reference, you can also check out this article for further guidance: How to memorize reports.