Hi Elizabeth-Klinga.

Let's check if this behavior is caused by a full cache. 

A cache temporary stores your browsing data, so when you revisit a web page, it reloads faster. When it's full, it can cause unusual behaviors in QuickBooks.

To start checking, you can open a private browser and access your client's company. This disables the cache from saving data, and it's a good way to check issues caused by a full cache. If there's no error, you can go back to your regular browser and clear the cached data. If it's the same thing, please try other browsers.

We're just around if you need more help.