Hi jamie, 

Thanks for posting in the Community. 

Let's check on your browser settings and ensure that you've enabled third party cookies. Here's how to enable third party cookies for some of the common browsers. 

Google Chrome:

1. Click on the 3 vertical dots in the top right corner.
2. Click on Settings, and then Advanced.
3. Click on Privacy and Security, and select Content Settings.
4. Select Cookies, and Turn off Block third-party cookies.

Safari:

1. Select the Gear Icon on your Safari browser.
2. Click on Preferences, then Privacy.
3. Under Block Cookies select Never.

Mozilla Firefox:

1. Click on the Settings menu at the top right corner, and select Options.
2. Click on Privacy.
3. Under History select Use custom settings for history.
4. Tick box for Accept cookies from sites.
5. Set Accept third party cookies to Always.

Once done, close the browser and relaunch it once more and access your QuickBooks Online account to check if you can access the Employees tab.

Let me know if you need further assistance and I'd be glad to help. Have a great day!