I'm here to help you get this resolved, @LeeAnne19.
To assist you better, we want to ask what specific error you encounter when switching between companies in your QuickBooks Online account. It will also significantly help us if you provide a screenshot.
In the meantime, I suggest performing browser troubleshooting options, as this may be a browser-induced issue. We can start with accessing your QuickBooks Online account through your browser's Incognito Mode.