Hello, @SZ12. Let's work together to resolve this matter and get your supplier information loading smoothly.
Ensure that you have a stable internet connection. A poor or intermittent internet connection can sometimes cause issues with QuickBooks Online. Otherwise, it can be due to outdated or corrupt cache files in your web browser. These files are stored to help websites load faster when you revisit them. Clearing them should help address the issue.
First, let's try accessing your account through an incognito window to rule out the possibility of a webpage issue. You can refer to these shortcut keys to open an incognito window in all supported browsers: