Hey there, guus.
When a browser stored a lot of caches, it could cause problems like bringing up the data to your account or latency issue. As an initial step, you can press the F5 key on your keyboard to refresh the page.
If you're still unable to access the URL, let's open your account in a private window. Simply press the following keyboard shortcut keys:
From the incognito window, access the URL from there. If you're able to open the link, go back to your regular browser and clear its cache. It could be that there's an issue with QuickBooks and the browser that you're using.
If the problem persists, I'd suggest following the steps below in reclassifying your transactions in QuickBooks Online.
You can go through this article: Reclassify or move multiple transactions at once. This will provide you others ways and steps on how to use the reclassify transactions tool n QuickBooks Accountant Online.
You can stay connected with me by adding a comment below if you have additional questions. I'll be your helping hand. Have a good one.