Thank you so much for sharing those details, Alert SIx Ltd. I would like for you to test something for me to rule out any browser-related issues. Open a private browser, log into your online account, and select that Advanced Search option. Below is the short cut option to do this.
If you can get the link to work, this indicates that your cache needs to be clear due to some form of data corruption. The instruction for how to do that for Google Chrome can be found in the article. However, with Quickbooks Online, there are other ways to search for transactions. You could do this by customer name, vendor name, and transaction type. Here's how for each:
Transaction Type (Sales)
Transaction Type (Expenses)
We're here if you have questions or need clarification. Simply leave your response below. My team and I will do our best to assist. Until then, be safe and take care.